remove Default from CandidateDescriptor (#4484)

* remove Default from CandidateHash * Apply suggestions from code review Co-authored-by: Andronik Ordian <write@reusable.software> * chore: fmt * remove backed candidate default * Partial migration away from CandidateReceipt::default * Remove more CandidateReceipt defaults * fmt * Mostly remove CommittedCandidateReceipt default usage * Remove CommittedCandidateReceipt * Remove more Defaults from polakdot primitives v1 + fmt * Remove more Default from polkadot primites v1 * WIP trying to get overseer example + tests to compile * feat: add primitives test helpers * reduce deps of helper * update primitive helpers * make candidate validation compile * fixup cargo lock * make av-store compile * fixup disputes coordinator tests * test: fixup backing * test: fixup approval voting * fixup bitfield signing * test: fixup runtime-api * test: fixup availability dist * foxi[ pverseer test] * remove some Defaults, remove bounds from `dummy` All `fn dummy` in primitives need to be removed anyways. This aids in the transition. * it's a test helper, so always use std * test: fixup parachains runtime tests Excluding benches. * fix keyring * fix paras runtime properly, no more default * Remove fn dummy() usage from approval voting * Move TestCandidateBuilder out of av store to test helpers * Make candidate validation tests pass * Make most dispute coirdinator tests pass * Make provisioner tests work * Make availability recovery tests work with test helpers * Update polkadot-collator-protocol tests * Update statement distribution tests * Update polkadot overseer examples and tests * Derive default for validation code so we don't break unrelated things * Make para runtime test pass (no bench) * Some more work * chore: cargo fmt * cargo fix * avoid some Default::default * fixup dispute coordinator test * remove unused crate deps * remove Default::default wherever possible, replace by dummy_* for the most part * chore: cargo fmt * Remove some warnings * Remove CommittedCandidateReceipt dummy * Remove CandidateReceipt dummy * Remove CandidateDescriptor dummy * Remove commented out code * Fix para runtime tests * chore: nightly * Some updates to the builder * Dynamically adjust mock head data size * Make dispute cooridinator tests work * Fix test candidate_backing_reorders_votes work * +nightly-2021-10-29 fmt * Spelling and remove a default use in builder * Various clean up * More small updates * fmt * More small updates * Doc comments for test helpers * cargo run --quiet --release --features=runtime-benchmarks -- benchmark --chain=kusama-dev --steps=50 --repeat=20 --pallet=runtime_parachains::paras_inherent --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --header=./file_header.txt --output=./runtime/kusama/src/weights/runtime_parachains_paras_inherent.rs * cargo run --quiet --release --features=runtime-benchmarks -- benchmark --chain=polkadot-dev --steps=50 --repeat=20 --pallet=runtime_parachains::paras_inherent --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --header=./file_header.txt --output=./runtime/polkadot/src/weights/runtime_parachains_paras_inherent.rs * Update lib.rs * review comments * fix warnings * fix test by using correct candidate receipt relay parent Co-authored-by: Andronik Ordian <write@reusable.software> Co-authored-by: emostov <32168567+emostov@users.noreply.github.com> Co-authored-by: Parity Bot <admin@parity.io> Co-authored-by: Gavin Wood <gavin@parity.io>
2026-06-11 21:11:07 +00:00 · 2021-12-10 13:12:07 +01:00
parent 916497e5db
commit 0f1a9fb1eb
68 changed files with 993 additions and 500 deletions
@@ -5820,6 +5820,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "rand 0.8.4",
 "sc-network",
 "sp-core",
@@ -5848,6 +5849,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "rand 0.8.4",
 "sc-network",
 "sp-application-crypto",
@@ -5928,6 +5930,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sc-network",
 "sp-core",
 "sp-keyring",
@@ -5968,6 +5971,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sc-keystore",
 "sc-network",
 "sp-application-crypto",
@@ -6033,6 +6037,7 @@ dependencies = [
 "polkadot-node-subsystem-util",
 "polkadot-overseer",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sc-network",
 "sp-consensus",
 "sp-core",
@@ -6052,6 +6057,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sp-core",
 "sp-maybe-compressed-blob",
 "thiserror",
@@ -6080,6 +6086,7 @@ dependencies = [
 "polkadot-node-subsystem-util",
 "polkadot-overseer",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "rand_core 0.5.1",
 "sc-keystore",
 "schnorrkel",
@@ -6115,6 +6122,7 @@ dependencies = [
 "polkadot-node-subsystem-util",
 "polkadot-overseer",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sp-core",
 "sp-keyring",
 "thiserror",
@@ -6134,6 +6142,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "polkadot-statement-table",
 "sc-keystore",
 "sp-application-crypto",
@@ -6154,6 +6163,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sp-keystore",
 "thiserror",
 "tracing",
@@ -6175,6 +6185,7 @@ dependencies = [
 "polkadot-node-subsystem-util",
 "polkadot-parachain",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sp-core",
 "sp-keyring",
 "sp-maybe-compressed-blob",
@@ -6226,8 +6237,6 @@ name = "polkadot-node-core-dispute-coordinator"
 version = "0.9.13"
 dependencies = [
 "assert_matches",
- "bitvec",
- "derive_more",
 "futures 0.3.18",
 "kvdb",
 "kvdb-memorydb",
@@ -6237,6 +6246,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sc-keystore",
 "sp-core",
 "sp-keyring",
@@ -6272,6 +6282,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sp-application-crypto",
 "sp-keystore",
 "thiserror",
@@ -6324,6 +6335,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sp-api",
 "sp-authority-discovery",
 "sp-consensus-babe",
@@ -6466,6 +6478,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-overseer",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "rand 0.8.4",
 "sp-application-crypto",
 "sp-core",
@@ -6492,6 +6505,7 @@ dependencies = [
 "polkadot-node-subsystem-types",
 "polkadot-overseer-gen",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sc-client-api",
 "sp-api",
 "sp-core",
@@ -6585,6 +6599,16 @@ dependencies = [
 "sp-version",
 ]

+[[package]]
+name = "polkadot-primitives-test-helpers"
+version = "0.9.13"
+dependencies = [
+ "polkadot-primitives",
+ "sp-application-crypto",
+ "sp-keyring",
+ "sp-runtime",
+]
+
 [[package]]
 name = "polkadot-rpc"
 version = "0.9.13"
@@ -6731,6 +6755,7 @@ dependencies = [
 "pallet-vesting",
 "parity-scale-codec",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "polkadot-runtime-parachains",
 "rustc-hex",
 "scale-info",
@@ -6776,6 +6801,7 @@ dependencies = [
 "pallet-vesting",
 "parity-scale-codec",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "rand 0.8.4",
 "rand_chacha 0.3.1",
 "rustc-hex",
@@ -6968,6 +6994,7 @@ dependencies = [
 "polkadot-node-subsystem-test-helpers",
 "polkadot-node-subsystem-util",
 "polkadot-primitives",
+ "polkadot-primitives-test-helpers",
 "sc-keystore",
 "sc-network",
 "sp-application-crypto",
@@ -27,6 +27,7 @@ members = [
 	"core-primitives",
 	"erasure-coding",
 	"primitives",
+	"primitives/test-helpers",
 	"runtime/common",
 	"runtime/common/slot_range_helper",
 	"runtime/parachains",
@@ -13,7 +13,7 @@ fn main() {

 			let available_data = AvailableData {
 				pov: Arc::new(pov_block),
-				validation_data: Default::default(),
+				validation_data: PersistedValidationData::default(),
 			};
 			let chunks = obtain_chunks_v1(
 				10,
@@ -370,7 +370,7 @@ impl<'a, I: Iterator<Item = &'a [u8]>> parity_scale_codec::Input for ShardInput<
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use polkadot_primitives::v0::{AvailableData, BlockData, PoVBlock};
+	use polkadot_primitives::v0::{AvailableData, BlockData, OmittedValidationData, PoVBlock};

 	// In order to adequately compute the number of entries in the Merkle
 	// trie, we must account for the fixed 16-ary trie structure.
@@ -385,7 +385,8 @@ mod tests {
 	fn round_trip_works() {
 		let pov_block = PoVBlock { block_data: BlockData((0..255).collect()) };

-		let available_data = AvailableData { pov_block, omitted_validation: Default::default() };
+		let available_data =
+			AvailableData { pov_block, omitted_validation: OmittedValidationData::default() };
 		let chunks = obtain_chunks(10, &available_data).unwrap();

 		assert_eq!(chunks.len(), 10);
@@ -413,7 +414,8 @@ mod tests {
 		let pov_block =
 			PoVBlock { block_data: BlockData(vec![2; n_validators / KEY_INDEX_NIBBLE_SIZE]) };

-		let available_data = AvailableData { pov_block, omitted_validation: Default::default() };
+		let available_data =
+			AvailableData { pov_block, omitted_validation: OmittedValidationData::default() };

 		let chunks = obtain_chunks(magnitude as usize, &available_data).unwrap();

@@ -19,3 +19,4 @@ parity-scale-codec = { version = "2.3.1", default-features = false, features = [

 [dev-dependencies]
 polkadot-node-subsystem-test-helpers = { path = "../subsystem-test-helpers" }
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../primitives/test-helpers" }
@@ -16,6 +16,7 @@

 mod handle_new_activations {
 	use super::super::*;
+	use ::test_helpers::{dummy_hash, dummy_head_data, dummy_validator};
 	use futures::{
 		lock::Mutex,
 		task::{Context as FuturesContext, Poll},
@@ -33,13 +34,13 @@ mod handle_new_activations {

 	fn test_collation() -> Collation {
 		Collation {
-			upward_messages: Default::default(),
-			horizontal_messages: Default::default(),
-			new_validation_code: Default::default(),
-			head_data: Default::default(),
+			upward_messages: vec![],
+			horizontal_messages: vec![],
+			new_validation_code: None,
+			head_data: dummy_head_data(),
 			proof_of_validity: PoV { block_data: BlockData(Vec::new()) },
-			processed_downward_messages: Default::default(),
-			hrmp_watermark: Default::default(),
+			processed_downward_messages: 0_u32,
+			hrmp_watermark: 0_u32.into(),
 		}
 	}

@@ -59,7 +60,7 @@ mod handle_new_activations {
 	}

 	fn test_validation_data() -> PersistedValidationData {
-		let mut persisted_validation_data: PersistedValidationData = Default::default();
+		let mut persisted_validation_data = PersistedValidationData::default();
 		persisted_validation_data.max_pov_size = 1024;
 		persisted_validation_data
 	}
@@ -106,7 +107,7 @@ mod handle_new_activations {
 						tx.send(Ok(vec![])).unwrap();
 					}
 					Some(AllMessages::RuntimeApi(RuntimeApiMessage::Request(_hash, RuntimeApiRequest::Validators(tx)))) => {
-						tx.send(Ok(vec![Default::default(); 3])).unwrap();
+						tx.send(Ok(vec![dummy_validator(); 3])).unwrap();
 					}
 					Some(msg) => panic!("didn't expect any other overseer requests given no availability cores; got {:?}", msg),
 				}
@@ -177,13 +178,13 @@ mod handle_new_activations {
 						),
 					))) => {
 						overseer_requested_validation_data.lock().await.push(hash);
-						tx.send(Ok(Default::default())).unwrap();
+						tx.send(Ok(None)).unwrap();
 					},
 					Some(AllMessages::RuntimeApi(RuntimeApiMessage::Request(
 						_hash,
 						RuntimeApiRequest::Validators(tx),
 					))) => {
-						tx.send(Ok(vec![Default::default(); 3])).unwrap();
+						tx.send(Ok(vec![dummy_validator(); 3])).unwrap();
 					},
 					Some(msg) => {
 						panic!("didn't expect any other overseer requests; got {:?}", msg)
@@ -254,7 +255,7 @@ mod handle_new_activations {
 						_hash,
 						RuntimeApiRequest::Validators(tx),
 					))) => {
-						tx.send(Ok(vec![Default::default(); 3])).unwrap();
+						tx.send(Ok(vec![dummy_validator(); 3])).unwrap();
 					},
 					Some(AllMessages::RuntimeApi(RuntimeApiMessage::Request(
 						_hash,
@@ -323,7 +324,7 @@ mod handle_new_activations {
 			collator: config.key.public(),
 			persisted_validation_data_hash: expect_validation_data_hash,
 			pov_hash: expect_pov_hash,
-			erasure_root: Default::default(), // this isn't something we're checking right now
+			erasure_root: dummy_hash(), // this isn't something we're checking right now
 			para_head: test_collation().head_data.hash(),
 			validation_code_hash: expect_validation_code_hash,
 		};
@@ -39,3 +39,4 @@ sp-consensus-babe = { git = "https://github.com/paritytech/substrate", branch =
 polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 assert_matches = "1.4.0"
 kvdb-memorydb = "0.10.0"
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../../primitives/test-helpers" }
@@ -457,25 +457,24 @@ pub fn tranches_to_approve(
 #[cfg(test)]
 mod tests {
 	use super::*;
-
-	use bitvec::{bitvec, order::Lsb0 as BitOrderLsb0};
+	use crate::{approval_db, BTreeMap};
+	use ::test_helpers::{dummy_candidate_receipt, dummy_hash};
+	use bitvec::{bitvec, order::Lsb0 as BitOrderLsb0, vec::BitVec};
 	use polkadot_primitives::v1::GroupIndex;

-	use crate::approval_db;
-
 	#[test]
 	fn pending_is_not_approved() {
 		let candidate = approval_db::v1::CandidateEntry {
-			candidate: Default::default(),
+			candidate: dummy_candidate_receipt(dummy_hash()),
 			session: 0,
-			block_assignments: Default::default(),
-			approvals: Default::default(),
+			block_assignments: BTreeMap::default(),
+			approvals: BitVec::default(),
 		}
 		.into();

 		let approval_entry = approval_db::v1::ApprovalEntry {
 			tranches: Vec::new(),
-			assignments: Default::default(),
+			assignments: BitVec::default(),
 			our_assignment: None,
 			our_approval_sig: None,
 			backing_group: GroupIndex(0),
@@ -499,9 +498,9 @@ mod tests {
 	#[test]
 	fn exact_takes_only_assignments_up_to() {
 		let mut candidate: CandidateEntry = approval_db::v1::CandidateEntry {
-			candidate: Default::default(),
+			candidate: dummy_candidate_receipt(dummy_hash()),
 			session: 0,
-			block_assignments: Default::default(),
+			block_assignments: BTreeMap::default(),
 			approvals: bitvec![BitOrderLsb0, u8; 0; 10],
 		}
 		.into();
@@ -571,9 +570,9 @@ mod tests {
 	#[test]
 	fn one_honest_node_always_approves() {
 		let mut candidate: CandidateEntry = approval_db::v1::CandidateEntry {
-			candidate: Default::default(),
+			candidate: dummy_candidate_receipt(dummy_hash()),
 			session: 0,
-			block_assignments: Default::default(),
+			block_assignments: BTreeMap::default(),
 			approvals: bitvec![BitOrderLsb0, u8; 0; 10],
 		}
 		.into();
@@ -1031,9 +1030,9 @@ mod tests {
 		let needed_approvals = 3;

 		let mut candidate: CandidateEntry = approval_db::v1::CandidateEntry {
-			candidate: Default::default(),
+			candidate: dummy_candidate_receipt(dummy_hash()),
 			session: 0,
-			block_assignments: Default::default(),
+			block_assignments: BTreeMap::default(),
 			approvals: bitvec![BitOrderLsb0, u8; 0; 3],
 		}
 		.into();
@@ -25,6 +25,8 @@ use kvdb::KeyValueDB;
 use polkadot_primitives::v1::Id as ParaId;
 use std::{collections::HashMap, sync::Arc};

+use ::test_helpers::{dummy_candidate_receipt, dummy_candidate_receipt_bad_sig, dummy_hash};
+
 const DATA_COL: u32 = 0;
 const NUM_COLUMNS: u32 = 1;

@@ -59,7 +61,7 @@ fn make_block_entry(
 }

 fn make_candidate(para_id: ParaId, relay_parent: Hash) -> CandidateReceipt {
-	let mut c = CandidateReceipt::default();
+	let mut c = dummy_candidate_receipt(dummy_hash());

 	c.descriptor.para_id = para_id;
 	c.descriptor.relay_parent = relay_parent;
@@ -73,7 +75,7 @@ fn read_write() {

 	let hash_a = Hash::repeat_byte(1);
 	let hash_b = Hash::repeat_byte(2);
-	let candidate_hash = CandidateReceipt::<Hash>::default().hash();
+	let candidate_hash = dummy_candidate_receipt_bad_sig(dummy_hash(), None).hash();

 	let range = StoredBlockRange(10, 20);
 	let at_height = vec![hash_a, hash_b];
@@ -82,7 +84,7 @@ fn read_write() {
 		make_block_entry(hash_a, Default::default(), 1, vec![(CoreIndex(0), candidate_hash)]);

 	let candidate_entry = CandidateEntry {
-		candidate: Default::default(),
+		candidate: dummy_candidate_receipt_bad_sig(dummy_hash(), None),
 		session: 5,
 		block_assignments: vec![(
 			hash_a,
@@ -264,7 +264,7 @@ pub(crate) fn compute_assignments(
 		match key {
 			None => {
 				tracing::trace!(target: LOG_TARGET, "No assignment key");
-				return Default::default()
+				return HashMap::new()
 			},
 			Some(k) => k,
 		}
@@ -320,7 +320,7 @@ fn compute_relay_vrf_modulo_assignments(
 	assignments: &mut HashMap<CoreIndex, OurAssignment>,
 ) {
 	for rvm_sample in 0..config.relay_vrf_modulo_samples {
-		let mut core = Default::default();
+		let mut core = CoreIndex::default();

 		let maybe_assignment = {
 			// Extra scope to ensure borrowing instead of moving core
@@ -575,6 +575,7 @@ pub(crate) async fn handle_new_head(
 pub(crate) mod tests {
 	use super::*;
 	use crate::approval_db::v1::DbBackend;
+	use ::test_helpers::{dummy_candidate_receipt, dummy_hash};
 	use assert_matches::assert_matches;
 	use kvdb::KeyValueDB;
 	use merlin::Transcript;
@@ -715,7 +716,7 @@ pub(crate) mod tests {

 		let hash = header.hash();
 		let make_candidate = |para_id| {
-			let mut r = CandidateReceipt::default();
+			let mut r = dummy_candidate_receipt(dummy_hash());
 			r.descriptor.para_id = para_id;
 			r.descriptor.relay_parent = hash;
 			r
@@ -829,7 +830,7 @@ pub(crate) mod tests {

 		let hash = header.hash();
 		let make_candidate = |para_id| {
-			let mut r = CandidateReceipt::default();
+			let mut r = dummy_candidate_receipt(dummy_hash());
 			r.descriptor.para_id = para_id;
 			r.descriptor.relay_parent = hash;
 			r
@@ -931,7 +932,7 @@ pub(crate) mod tests {

 		let hash = header.hash();
 		let make_candidate = |para_id| {
-			let mut r = CandidateReceipt::default();
+			let mut r = dummy_candidate_receipt(dummy_hash());
 			r.descriptor.para_id = para_id;
 			r.descriptor.relay_parent = hash;
 			r
@@ -1021,7 +1022,7 @@ pub(crate) mod tests {

 		let hash = header.hash();
 		let make_candidate = |para_id| {
-			let mut r = CandidateReceipt::default();
+			let mut r = dummy_candidate_receipt(dummy_hash());
 			r.descriptor.para_id = para_id;
 			r.descriptor.relay_parent = hash;
 			r
@@ -1163,7 +1164,7 @@ pub(crate) mod tests {

 		let hash = header.hash();
 		let make_candidate = |para_id| {
-			let mut r = CandidateReceipt::default();
+			let mut r = dummy_candidate_receipt(dummy_hash());
 			r.descriptor.para_id = para_id;
 			r.descriptor.relay_parent = hash;
 			r
@@ -51,6 +51,8 @@ use super::{
 	},
 };

+use ::test_helpers::{dummy_candidate_receipt, dummy_candidate_receipt_bad_sig};
+
 const SLOT_DURATION_MILLIS: u64 = 5000;

 #[derive(Clone)]
@@ -547,9 +549,8 @@ where
 }

 fn make_candidate(para_id: ParaId, hash: &Hash) -> CandidateReceipt {
-	let mut r = CandidateReceipt::default();
+	let mut r = dummy_candidate_receipt_bad_sig(hash.clone(), Some(Default::default()));
 	r.descriptor.para_id = para_id;
-	r.descriptor.relay_parent = hash.clone();
 	r
 }

@@ -1132,7 +1133,7 @@ fn subsystem_rejects_approval_if_no_block_entry() {
 		let block_hash = Hash::repeat_byte(0x01);
 		let candidate_index = 0;
 		let validator = ValidatorIndex(0);
-		let candidate_hash = CandidateReceipt::<Hash>::default().hash();
+		let candidate_hash = dummy_candidate_receipt(block_hash).hash();
 		let session_index = 1;

 		let rx = check_and_import_approval(
@@ -1168,7 +1169,8 @@ fn subsystem_rejects_approval_before_assignment() {
 		let block_hash = Hash::repeat_byte(0x01);

 		let candidate_hash = {
-			let mut candidate_receipt = CandidateReceipt::<Hash>::default();
+			let mut candidate_receipt =
+				dummy_candidate_receipt_bad_sig(block_hash, Some(Default::default()));
 			candidate_receipt.descriptor.para_id = 0.into();
 			candidate_receipt.descriptor.relay_parent = block_hash;
 			candidate_receipt.hash()
@@ -1358,7 +1360,8 @@ fn subsystem_accepts_and_imports_approval_after_assignment() {
 		let block_hash = Hash::repeat_byte(0x01);

 		let candidate_hash = {
-			let mut candidate_receipt = CandidateReceipt::<Hash>::default();
+			let mut candidate_receipt =
+				dummy_candidate_receipt_bad_sig(block_hash, Some(Default::default()));
 			candidate_receipt.descriptor.para_id = 0.into();
 			candidate_receipt.descriptor.relay_parent = block_hash;
 			candidate_receipt.hash()
@@ -1423,7 +1426,8 @@ fn subsystem_second_approval_import_only_schedules_wakeups() {
 		let block_hash = Hash::repeat_byte(0x01);

 		let candidate_hash = {
-			let mut candidate_receipt = CandidateReceipt::<Hash>::default();
+			let mut candidate_receipt =
+				dummy_candidate_receipt_bad_sig(block_hash, Some(Default::default()));
 			candidate_receipt.descriptor.para_id = 0.into();
 			candidate_receipt.descriptor.relay_parent = block_hash;
 			candidate_receipt.hash()
@@ -1886,12 +1890,12 @@ fn subsystem_import_checked_approval_sets_one_block_bit_at_a_time() {
 		let block_hash = Hash::repeat_byte(0x01);

 		let candidate_receipt1 = {
-			let mut receipt = CandidateReceipt::<Hash>::default();
+			let mut receipt = dummy_candidate_receipt(block_hash);
 			receipt.descriptor.para_id = 1.into();
 			receipt
 		};
 		let candidate_receipt2 = {
-			let mut receipt = CandidateReceipt::<Hash>::default();
+			let mut receipt = dummy_candidate_receipt(block_hash);
 			receipt.descriptor.para_id = 2.into();
 			receipt
 		};
@@ -2032,9 +2036,8 @@ fn approved_ancestor_test(
 			.iter()
 			.enumerate()
 			.map(|(i, hash)| {
-				let mut candidate_receipt = CandidateReceipt::<Hash>::default();
+				let mut candidate_receipt = dummy_candidate_receipt(*hash);
 				candidate_receipt.descriptor.para_id = i.into();
-				candidate_receipt.descriptor.relay_parent = *hash;
 				candidate_receipt
 			})
 			.collect();
@@ -2183,7 +2186,7 @@ fn subsystem_process_wakeup_trigger_assignment_launch_approval() {
 		} = test_harness;

 		let block_hash = Hash::repeat_byte(0x01);
-		let candidate_receipt = CandidateReceipt::<Hash>::default();
+		let candidate_receipt = dummy_candidate_receipt(block_hash);
 		let candidate_hash = candidate_receipt.hash();
 		let slot = Slot::from(1);
 		let candidate_index = 0;
@@ -2317,7 +2320,7 @@ where
 		} = test_harness;

 		let block_hash = Hash::repeat_byte(0x01);
-		let candidate_receipt = CandidateReceipt::<Hash>::default();
+		let candidate_receipt = dummy_candidate_receipt(block_hash);
 		let candidate_hash = candidate_receipt.hash();
 		let slot = Slot::from(1);
 		let candidate_index = 0;
@@ -31,3 +31,4 @@ polkadot-node-subsystem-util = { path = "../../subsystem-util" }
 polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }
 parking_lot = "0.11.1"
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../../primitives/test-helpers" }
@@ -21,13 +21,14 @@ use std::convert::TryFrom;
 use assert_matches::assert_matches;
 use futures::{channel::oneshot, executor, future, Future};

+use ::test_helpers::TestCandidateBuilder;
 use parking_lot::Mutex;
 use polkadot_node_primitives::{AvailableData, BlockData, PoV, Proof};
 use polkadot_node_subsystem_test_helpers as test_helpers;
 use polkadot_node_subsystem_util::TimeoutExt;
 use polkadot_primitives::v1::{
-	CandidateDescriptor, CandidateHash, CandidateReceipt, CoreIndex, GroupIndex, HeadData, Header,
-	Id as ParaId, PersistedValidationData, ValidatorId,
+	CandidateHash, CandidateReceipt, CoreIndex, GroupIndex, HeadData, Header,
+	PersistedValidationData, ValidatorId,
 };
 use polkadot_subsystem::{
 	errors::RuntimeApiError,
@@ -47,28 +48,6 @@ const TEST_CONFIG: Config = Config { col_data: columns::DATA, col_meta: columns:

 type VirtualOverseer = test_helpers::TestSubsystemContextHandle<AvailabilityStoreMessage>;

-#[derive(Default)]
-struct TestCandidateBuilder {
-	para_id: ParaId,
-	pov_hash: Hash,
-	relay_parent: Hash,
-	commitments_hash: Hash,
-}
-
-impl TestCandidateBuilder {
-	fn build(self) -> CandidateReceipt {
-		CandidateReceipt {
-			descriptor: CandidateDescriptor {
-				para_id: self.para_id,
-				pov_hash: self.pov_hash,
-				relay_parent: self.relay_parent,
-				..Default::default()
-			},
-			commitments_hash: self.commitments_hash,
-		}
-	}
-}
-
 #[derive(Clone)]
 struct TestClock {
 	inner: Arc<Mutex<Duration>>,
@@ -26,3 +26,4 @@ sp-tracing = { git = "https://github.com/paritytech/substrate", branch = "master
 futures = { version = "0.3.17", features = ["thread-pool"] }
 assert_matches = "1.4.0"
 polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../../primitives/test-helpers" }
@@ -15,12 +15,16 @@
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.

 use super::*;
+use ::test_helpers::{
+	dummy_candidate_receipt_bad_sig, dummy_collator, dummy_collator_signature,
+	dummy_committed_candidate_receipt, dummy_hash, dummy_validation_code,
+};
 use assert_matches::assert_matches;
 use futures::{future, Future};
 use polkadot_node_primitives::{BlockData, InvalidCandidate};
 use polkadot_node_subsystem_test_helpers as test_helpers;
 use polkadot_primitives::v1::{
-	GroupRotationInfo, HeadData, PersistedValidationData, ScheduledCore,
+	CollatorId, GroupRotationInfo, HeadData, PersistedValidationData, ScheduledCore,
 };
 use polkadot_subsystem::{
 	messages::{CollatorProtocolMessage, RuntimeApiMessage, RuntimeApiRequest},
@@ -118,9 +122,9 @@ impl Default for TestState {

 		let validation_data = PersistedValidationData {
 			parent_head: HeadData(vec![7, 8, 9]),
-			relay_parent_number: Default::default(),
+			relay_parent_number: 0_u32.into(),
 			max_pov_size: 1024,
-			relay_parent_storage_root: Default::default(),
+			relay_parent_storage_root: dummy_hash(),
 		};

 		Self {
@@ -189,9 +193,20 @@ impl TestCandidateBuilder {
 				pov_hash: self.pov_hash,
 				relay_parent: self.relay_parent,
 				erasure_root: self.erasure_root,
-				..Default::default()
+				collator: dummy_collator(),
+				signature: dummy_collator_signature(),
+				para_head: dummy_hash(),
+				validation_code_hash: dummy_validation_code().hash(),
+				persisted_validation_data_hash: dummy_hash(),
+			},
+			commitments: CandidateCommitments {
+				head_data: self.head_data,
+				upward_messages: vec![],
+				horizontal_messages: vec![],
+				new_validation_code: None,
+				processed_downward_messages: 0,
+				hrmp_watermark: 0_u32,
 			},
-			commitments: CandidateCommitments { head_data: self.head_data, ..Default::default() },
 		}
 	}
 }
@@ -1445,7 +1460,8 @@ fn candidate_backing_reorders_votes() {
 	};

 	let fake_attestation = |idx: u32| {
-		let candidate: CommittedCandidateReceipt = Default::default();
+		let candidate =
+			dummy_candidate_receipt_bad_sig(Default::default(), Some(Default::default()));
 		let hash = candidate.hash();
 		let mut data = vec![0; 64];
 		data[0..32].copy_from_slice(hash.0.as_bytes());
@@ -1456,7 +1472,7 @@ fn candidate_backing_reorders_votes() {
 	};

 	let attested = TableAttestedCandidate {
-		candidate: Default::default(),
+		candidate: dummy_committed_candidate_receipt(dummy_hash()),
 		validity_votes: vec![
 			(ValidatorIndex(5), fake_attestation(5)),
 			(ValidatorIndex(3), fake_attestation(3)),
@@ -16,3 +16,4 @@ thiserror = "1.0.30"

 [dev-dependencies]
 polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../../primitives/test-helpers" }
@@ -18,6 +18,7 @@ use super::*;
 use futures::{executor::block_on, pin_mut};
 use polkadot_node_subsystem::messages::AllMessages;
 use polkadot_primitives::v1::{CandidateHash, OccupiedCore};
+use test_helpers::dummy_candidate_descriptor;

 fn occupied_core(para_id: u32, candidate_hash: CandidateHash) -> CoreState {
 	CoreState::Occupied(OccupiedCore {
@@ -28,7 +29,7 @@ fn occupied_core(para_id: u32, candidate_hash: CandidateHash) -> CoreState {
 		next_up_on_time_out: None,
 		availability: Default::default(),
 		candidate_hash,
-		candidate_descriptor: Default::default(),
+		candidate_descriptor: dummy_candidate_descriptor(Hash::zero()),
 	})
 }

@@ -27,3 +27,4 @@ futures = { version = "0.3.17", features = ["thread-pool"] }
 assert_matches = "1.4.0"
 polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../../primitives/test-helpers" }
@@ -15,6 +15,7 @@
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.

 use super::*;
+use ::test_helpers::{dummy_hash, make_valid_candidate_descriptor};
 use assert_matches::assert_matches;
 use futures::executor;
 use polkadot_node_core_pvf::PrepareError;
@@ -25,20 +26,6 @@ use polkadot_primitives::v1::{HeadData, UpwardMessage};
 use sp_core::testing::TaskExecutor;
 use sp_keyring::Sr25519Keyring;

-fn collator_sign(descriptor: &mut CandidateDescriptor, collator: Sr25519Keyring) {
-	descriptor.collator = collator.public().into();
-	let payload = polkadot_primitives::v1::collator_signature_payload(
-		&descriptor.relay_parent,
-		&descriptor.para_id,
-		&descriptor.persisted_validation_data_hash,
-		&descriptor.pov_hash,
-		&descriptor.validation_code_hash,
-	);
-
-	descriptor.signature = collator.sign(&payload[..]).into();
-	assert!(descriptor.check_collator_signature().is_ok());
-}
-
 #[test]
 fn correctly_checks_included_assumption() {
 	let validation_data: PersistedValidationData = Default::default();
@@ -48,10 +35,16 @@ fn correctly_checks_included_assumption() {
 	let relay_parent = [2; 32].into();
 	let para_id = 5.into();

-	let mut candidate = CandidateDescriptor::default();
-	candidate.relay_parent = relay_parent;
-	candidate.persisted_validation_data_hash = persisted_validation_data_hash;
-	candidate.para_id = para_id;
+	let descriptor = make_valid_candidate_descriptor(
+		para_id,
+		relay_parent,
+		persisted_validation_data_hash,
+		dummy_hash(),
+		dummy_hash(),
+		dummy_hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let pool = TaskExecutor::new();
 	let (mut ctx, mut ctx_handle) =
@@ -59,7 +52,7 @@ fn correctly_checks_included_assumption() {

 	let (check_fut, check_result) = check_assumption_validation_data(
 		ctx.sender(),
-		&candidate,
+		&descriptor,
 		OccupiedCoreAssumption::Included,
 	)
 	.remote_handle();
@@ -114,10 +107,16 @@ fn correctly_checks_timed_out_assumption() {
 	let relay_parent = [2; 32].into();
 	let para_id = 5.into();

-	let mut candidate = CandidateDescriptor::default();
-	candidate.relay_parent = relay_parent;
-	candidate.persisted_validation_data_hash = persisted_validation_data_hash;
-	candidate.para_id = para_id;
+	let descriptor = make_valid_candidate_descriptor(
+		para_id,
+		relay_parent,
+		persisted_validation_data_hash,
+		dummy_hash(),
+		dummy_hash(),
+		dummy_hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let pool = TaskExecutor::new();
 	let (mut ctx, mut ctx_handle) =
@@ -125,7 +124,7 @@ fn correctly_checks_timed_out_assumption() {

 	let (check_fut, check_result) = check_assumption_validation_data(
 		ctx.sender(),
-		&candidate,
+		&descriptor,
 		OccupiedCoreAssumption::TimedOut,
 	)
 	.remote_handle();
@@ -178,10 +177,16 @@ fn check_is_bad_request_if_no_validation_data() {
 	let relay_parent = [2; 32].into();
 	let para_id = 5.into();

-	let mut candidate = CandidateDescriptor::default();
-	candidate.relay_parent = relay_parent;
-	candidate.persisted_validation_data_hash = persisted_validation_data_hash;
-	candidate.para_id = para_id;
+	let descriptor = make_valid_candidate_descriptor(
+		para_id,
+		relay_parent,
+		persisted_validation_data_hash,
+		dummy_hash(),
+		dummy_hash(),
+		dummy_hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let pool = TaskExecutor::new();
 	let (mut ctx, mut ctx_handle) =
@@ -189,7 +194,7 @@ fn check_is_bad_request_if_no_validation_data() {

 	let (check_fut, check_result) = check_assumption_validation_data(
 		ctx.sender(),
-		&candidate,
+		&descriptor,
 		OccupiedCoreAssumption::Included,
 	)
 	.remote_handle();
@@ -226,10 +231,16 @@ fn check_is_bad_request_if_no_validation_code() {
 	let relay_parent = [2; 32].into();
 	let para_id = 5.into();

-	let mut candidate = CandidateDescriptor::default();
-	candidate.relay_parent = relay_parent;
-	candidate.persisted_validation_data_hash = persisted_validation_data_hash;
-	candidate.para_id = para_id;
+	let descriptor = make_valid_candidate_descriptor(
+		para_id,
+		relay_parent,
+		persisted_validation_data_hash,
+		dummy_hash(),
+		dummy_hash(),
+		dummy_hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let pool = TaskExecutor::new();
 	let (mut ctx, mut ctx_handle) =
@@ -237,7 +248,7 @@ fn check_is_bad_request_if_no_validation_code() {

 	let (check_fut, check_result) = check_assumption_validation_data(
 		ctx.sender(),
-		&candidate,
+		&descriptor,
 		OccupiedCoreAssumption::TimedOut,
 	)
 	.remote_handle();
@@ -286,10 +297,16 @@ fn check_does_not_match() {
 	let relay_parent = [2; 32].into();
 	let para_id = 5.into();

-	let mut candidate = CandidateDescriptor::default();
-	candidate.relay_parent = relay_parent;
-	candidate.persisted_validation_data_hash = [3; 32].into();
-	candidate.para_id = para_id;
+	let descriptor = make_valid_candidate_descriptor(
+		para_id,
+		relay_parent,
+		Hash::from([3; 32]),
+		dummy_hash(),
+		dummy_hash(),
+		dummy_hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let pool = TaskExecutor::new();
 	let (mut ctx, mut ctx_handle) =
@@ -297,7 +314,7 @@ fn check_does_not_match() {

 	let (check_fut, check_result) = check_assumption_validation_data(
 		ctx.sender(),
-		&candidate,
+		&descriptor,
 		OccupiedCoreAssumption::Included,
 	)
 	.remote_handle();
@@ -361,11 +378,16 @@ fn candidate_validation_ok_is_ok() {
 	let head_data = HeadData(vec![1, 1, 1]);
 	let validation_code = ValidationCode(vec![2; 16]);

-	let mut descriptor = CandidateDescriptor::default();
-	descriptor.pov_hash = pov.hash();
-	descriptor.para_head = head_data.hash();
-	descriptor.validation_code_hash = validation_code.hash();
-	collator_sign(&mut descriptor, Sr25519Keyring::Alice);
+	let descriptor = make_valid_candidate_descriptor(
+		1.into(),
+		dummy_hash(),
+		validation_data.hash(),
+		pov.hash(),
+		validation_code.hash(),
+		head_data.hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let check = perform_basic_checks(
 		&descriptor,
@@ -412,10 +434,16 @@ fn candidate_validation_bad_return_is_invalid() {
 	let pov = PoV { block_data: BlockData(vec![1; 32]) };
 	let validation_code = ValidationCode(vec![2; 16]);

-	let mut descriptor = CandidateDescriptor::default();
-	descriptor.pov_hash = pov.hash();
-	descriptor.validation_code_hash = validation_code.hash();
-	collator_sign(&mut descriptor, Sr25519Keyring::Alice);
+	let descriptor = make_valid_candidate_descriptor(
+		1.into(),
+		dummy_hash(),
+		validation_data.hash(),
+		pov.hash(),
+		validation_code.hash(),
+		dummy_hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let check = perform_basic_checks(
 		&descriptor,
@@ -448,10 +476,16 @@ fn candidate_validation_timeout_is_internal_error() {
 	let pov = PoV { block_data: BlockData(vec![1; 32]) };
 	let validation_code = ValidationCode(vec![2; 16]);

-	let mut descriptor = CandidateDescriptor::default();
-	descriptor.pov_hash = pov.hash();
-	descriptor.validation_code_hash = validation_code.hash();
-	collator_sign(&mut descriptor, Sr25519Keyring::Alice);
+	let descriptor = make_valid_candidate_descriptor(
+		1.into(),
+		dummy_hash(),
+		validation_data.hash(),
+		pov.hash(),
+		validation_code.hash(),
+		dummy_hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let check = perform_basic_checks(
 		&descriptor,
@@ -483,10 +517,16 @@ fn candidate_validation_code_mismatch_is_invalid() {
 	let pov = PoV { block_data: BlockData(vec![1; 32]) };
 	let validation_code = ValidationCode(vec![2; 16]);

-	let mut descriptor = CandidateDescriptor::default();
-	descriptor.pov_hash = pov.hash();
-	descriptor.validation_code_hash = ValidationCode(vec![1; 16]).hash();
-	collator_sign(&mut descriptor, Sr25519Keyring::Alice);
+	let descriptor = make_valid_candidate_descriptor(
+		1.into(),
+		dummy_hash(),
+		validation_data.hash(),
+		pov.hash(),
+		ValidationCode(vec![1; 16]).hash(),
+		dummy_hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let check = perform_basic_checks(
 		&descriptor,
@@ -523,11 +563,16 @@ fn compressed_code_works() {
 		.map(ValidationCode)
 		.unwrap();

-	let mut descriptor = CandidateDescriptor::default();
-	descriptor.pov_hash = pov.hash();
-	descriptor.para_head = head_data.hash();
-	descriptor.validation_code_hash = validation_code.hash();
-	collator_sign(&mut descriptor, Sr25519Keyring::Alice);
+	let descriptor = make_valid_candidate_descriptor(
+		1.into(),
+		dummy_hash(),
+		validation_data.hash(),
+		pov.hash(),
+		validation_code.hash(),
+		head_data.hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let validation_result = WasmValidationResult {
 		head_data,
@@ -563,11 +608,16 @@ fn code_decompression_failure_is_invalid() {
 			.map(ValidationCode)
 			.unwrap();

-	let mut descriptor = CandidateDescriptor::default();
-	descriptor.pov_hash = pov.hash();
-	descriptor.para_head = head_data.hash();
-	descriptor.validation_code_hash = validation_code.hash();
-	collator_sign(&mut descriptor, Sr25519Keyring::Alice);
+	let descriptor = make_valid_candidate_descriptor(
+		1.into(),
+		dummy_hash(),
+		validation_data.hash(),
+		pov.hash(),
+		validation_code.hash(),
+		head_data.hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let validation_result = WasmValidationResult {
 		head_data,
@@ -604,11 +654,16 @@ fn pov_decompression_failure_is_invalid() {

 	let validation_code = ValidationCode(vec![2; 16]);

-	let mut descriptor = CandidateDescriptor::default();
-	descriptor.pov_hash = pov.hash();
-	descriptor.para_head = head_data.hash();
-	descriptor.validation_code_hash = validation_code.hash();
-	collator_sign(&mut descriptor, Sr25519Keyring::Alice);
+	let descriptor = make_valid_candidate_descriptor(
+		1.into(),
+		dummy_hash(),
+		validation_data.hash(),
+		pov.hash(),
+		validation_code.hash(),
+		head_data.hash(),
+		dummy_hash(),
+		Sr25519Keyring::Alice,
+	);

 	let validation_result = WasmValidationResult {
 		head_data,
@@ -5,12 +5,10 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"

 [dependencies]
-bitvec = { version = "0.20.1", default-features = false, features = ["alloc"] }
 futures = "0.3.17"
 tracing = "0.1.29"
 parity-scale-codec = "2"
 kvdb = "0.10.0"
-derive_more = "0.99.17"
 thiserror = "1.0.30"

 polkadot-primitives = { path = "../../../primitives" }
@@ -27,6 +25,7 @@ sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-keystore = { git = "https://github.com/paritytech/substrate", branch = "master" }
 assert_matches = "1.4.0"
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../../primitives/test-helpers" }

 [features]
 # If not enabled, the dispute coordinator will do nothing.
@@ -252,6 +252,7 @@ pub(crate) fn note_current_session(
 #[cfg(test)]
 mod tests {
 	use super::*;
+	use ::test_helpers::{dummy_candidate_receipt, dummy_hash};
 	use polkadot_primitives::v1::{Hash, Id as ParaId};

 	fn make_db() -> DbBackend {
@@ -285,7 +286,7 @@ mod tests {
 			1,
 			CandidateHash(Hash::repeat_byte(1)),
 			CandidateVotes {
-				candidate_receipt: Default::default(),
+				candidate_receipt: dummy_candidate_receipt(dummy_hash()),
 				valid: Vec::new(),
 				invalid: Vec::new(),
 			},
@@ -295,7 +296,7 @@ mod tests {
 			CandidateHash(Hash::repeat_byte(1)),
 			CandidateVotes {
 				candidate_receipt: {
-					let mut receipt = CandidateReceipt::default();
+					let mut receipt = dummy_candidate_receipt(dummy_hash());
 					receipt.descriptor.para_id = 5.into();

 					receipt
@@ -362,7 +363,7 @@ mod tests {
 			1,
 			CandidateHash(Hash::repeat_byte(1)),
 			CandidateVotes {
-				candidate_receipt: Default::default(),
+				candidate_receipt: dummy_candidate_receipt(dummy_hash()),
 				valid: Vec::new(),
 				invalid: Vec::new(),
 			},
@@ -379,7 +380,7 @@ mod tests {
 				.candidate_receipt
 				.descriptor
 				.para_id,
-			ParaId::from(0),
+			ParaId::from(1),
 		);

 		let mut overlay_db = OverlayedBackend::new(&backend);
@@ -388,7 +389,7 @@ mod tests {
 			CandidateHash(Hash::repeat_byte(1)),
 			CandidateVotes {
 				candidate_receipt: {
-					let mut receipt = CandidateReceipt::default();
+					let mut receipt = dummy_candidate_receipt(dummy_hash());
 					receipt.descriptor.para_id = 5.into();

 					receipt
@@ -427,7 +428,7 @@ mod tests {
 		let very_recent = current_session - 1;

 		let blank_candidate_votes = || CandidateVotes {
-			candidate_receipt: Default::default(),
+			candidate_receipt: dummy_candidate_receipt(dummy_hash()),
 			valid: Vec::new(),
 			invalid: Vec::new(),
 		};
@@ -62,6 +62,7 @@ pub struct OrderingProvider {
 /// we are already too late. The ordering mechanism here serves to prevent this from happening in
 /// the first place.
 #[derive(Copy, Clone)]
+#[cfg_attr(test, derive(Debug))]
 pub struct CandidateComparator {
 	/// Block number of the relay parent.
 	///
@@ -150,7 +151,7 @@ impl OrderingProvider {
 			None => {
 				tracing::warn!(
 					target: LOG_TARGET,
-					candidate_hash = ?candidate.hash(),
+					candidate_hash = ?candidate_hash,
 					"Candidate's relay_parent could not be found via chain API, but we saw candidate included?!"
 				);
 				return Ok(None)
@@ -22,6 +22,7 @@ use futures::FutureExt;
 use parity_scale_codec::Encode;
 use sp_core::testing::TaskExecutor;

+use ::test_helpers::{dummy_collator, dummy_collator_signature, dummy_hash};
 use polkadot_node_subsystem::{
 	jaeger,
 	messages::{
@@ -35,8 +36,8 @@ use polkadot_node_subsystem_test_helpers::{
 };
 use polkadot_node_subsystem_util::reexports::SubsystemContext;
 use polkadot_primitives::v1::{
-	BlakeTwo256, BlockNumber, CandidateEvent, CandidateReceipt, CoreIndex, GroupIndex, Hash, HashT,
-	HeadData,
+	BlakeTwo256, BlockNumber, CandidateDescriptor, CandidateEvent, CandidateReceipt, CoreIndex,
+	GroupIndex, Hash, HashT, HeadData,
 };

 use super::OrderingProvider;
@@ -90,12 +91,14 @@ fn launch_virtual_overseer(ctx: &mut impl SubsystemContext, ctx_handle: VirtualO
 }

 async fn virtual_overseer(mut ctx_handle: VirtualOverseer) {
-	let ev = vec![CandidateEvent::CandidateIncluded(
-		CandidateReceipt::default(),
-		HeadData::default(),
-		CoreIndex::from(0),
-		GroupIndex::from(0),
-	)];
+	let create_ev = |relay_parent: Hash| {
+		vec![CandidateEvent::CandidateIncluded(
+			make_candidate_receipt(relay_parent),
+			HeadData::default(),
+			CoreIndex::from(0),
+			GroupIndex::from(0),
+		)]
+	};

 	assert_matches!(
 		ctx_handle.recv().await,
@@ -111,17 +114,17 @@ async fn virtual_overseer(mut ctx_handle: VirtualOverseer) {
 	assert_matches!(
 		ctx_handle.recv().await,
 		AllMessages::RuntimeApi(RuntimeApiMessage::Request(
-				_,
+				relay_parent,
 				RuntimeApiRequest::CandidateEvents(
 					tx,
 					)
 				)) => {
-			tx.send(Ok(ev)).unwrap();
+			tx.send(Ok(create_ev(relay_parent))).unwrap();
 		}
 	);
 	assert_matches!(
 		ctx_handle.recv().await,
-		AllMessages::ChainApi(ChainApiMessage::BlockNumber(_, tx)) => {
+		AllMessages::ChainApi(ChainApiMessage::BlockNumber(_relay_parent, tx)) => {
 			tx.send(Ok(Some(1))).unwrap();
 		}
 	);
@@ -142,24 +145,39 @@ fn get_block_number_hash(n: BlockNumber) -> Hash {
 	BlakeTwo256::hash(&n.encode())
 }

+fn make_candidate_receipt(relay_parent: Hash) -> CandidateReceipt {
+	let zeros = dummy_hash();
+	let descriptor = CandidateDescriptor {
+		para_id: 0.into(),
+		relay_parent,
+		collator: dummy_collator(),
+		persisted_validation_data_hash: zeros,
+		pov_hash: zeros,
+		erasure_root: zeros,
+		signature: dummy_collator_signature(),
+		para_head: zeros,
+		validation_code_hash: zeros.into(),
+	};
+	let candidate = CandidateReceipt { descriptor, commitments_hash: zeros };
+	candidate
+}
+
 #[test]
 fn ordering_provider_provides_ordering_when_initialized() {
+	let candidate = make_candidate_receipt(get_block_number_hash(2));
 	futures::executor::block_on(async {
 		let mut state = TestState::new().await;
 		let r = state
 			.ordering
-			.candidate_comparator(state.ctx.sender(), &CandidateReceipt::default())
+			.candidate_comparator(state.ctx.sender(), &candidate)
 			.await
 			.unwrap();
-		assert!(r.is_none());
+		assert_matches!(r, None);
 		// After next active leaves update we should have a comparator:
 		state.process_active_leaves_update().await;
-		let r = state
-			.ordering
-			.candidate_comparator(state.ctx.sender(), &CandidateReceipt::default())
-			.await
-			.unwrap();
-		assert!(r.is_some());
-		assert_eq!(r.unwrap().relay_parent_block_number, 1);
+		let r = state.ordering.candidate_comparator(state.ctx.sender(), &candidate).await;
+		assert_matches!(r, Ok(Some(r2)) => {
+			assert_eq!(r2.relay_parent_block_number, 1);
+		});
 	});
 }
@@ -14,8 +14,9 @@
 // You should have received a copy of the GNU General Public License
 // along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.

+use ::test_helpers::{dummy_candidate_receipt, dummy_hash};
 use assert_matches::assert_matches;
-use polkadot_primitives::v1::{BlockNumber, CandidateReceipt, Hash};
+use polkadot_primitives::v1::{BlockNumber, Hash};

 use crate::real::ordering::CandidateComparator;

@@ -23,7 +24,7 @@ use super::{Error, ParticipationRequest, Queues};

 /// Make a `ParticipationRequest` based on the given commitments hash.
 fn make_participation_request(hash: Hash) -> ParticipationRequest {
-	let mut receipt = CandidateReceipt::default();
+	let mut receipt = dummy_candidate_receipt(dummy_hash());
 	// make it differ:
 	receipt.commitments_hash = hash;
 	ParticipationRequest::new(receipt, 1, 100)
@@ -22,6 +22,9 @@ use std::{sync::Arc, time::Duration};
 use sp_core::testing::TaskExecutor;

 use super::*;
+use ::test_helpers::{
+	dummy_candidate_commitments, dummy_candidate_receipt_bad_sig, dummy_digest, dummy_hash,
+};
 use parity_scale_codec::Encode;
 use polkadot_node_primitives::{AvailableData, BlockData, InvalidCandidate, PoV};
 use polkadot_node_subsystem::{
@@ -35,7 +38,9 @@ use polkadot_node_subsystem::{
 use polkadot_node_subsystem_test_helpers::{
 	make_subsystem_context, TestSubsystemContext, TestSubsystemContextHandle,
 };
-use polkadot_primitives::v1::{BlakeTwo256, CandidateCommitments, HashT, Header, ValidationCode};
+use polkadot_primitives::v1::{
+	BlakeTwo256, CandidateCommitments, HashT, Header, PersistedValidationData, ValidationCode,
+};

 type VirtualOverseer = TestSubsystemContextHandle<DisputeCoordinatorMessage>;

@@ -62,7 +67,7 @@ async fn participate_with_commitments_hash(
 	commitments_hash: Hash,
 ) -> Result<()> {
 	let candidate_receipt = {
-		let mut receipt = CandidateReceipt::default();
+		let mut receipt = dummy_candidate_receipt_bad_sig(dummy_hash(), dummy_hash());
 		receipt.commitments_hash = commitments_hash;
 		receipt
 	};
@@ -82,9 +87,9 @@ async fn activate_leaf(
 	let block_header = Header {
 		parent_hash: BlakeTwo256::hash(&block_number.encode()),
 		number: block_number,
-		digest: Default::default(),
-		state_root: Default::default(),
-		extrinsics_root: Default::default(),
+		digest: dummy_digest(),
+		state_root: dummy_hash(),
+		extrinsics_root: dummy_hash(),
 	};

 	let block_hash = block_header.hash();
@@ -113,7 +118,7 @@ pub async fn participation_full_happy_path(ctx_handle: &mut VirtualOverseer) {
 	AllMessages::CandidateValidation(
 		CandidateValidationMessage::ValidateFromExhaustive(_, _, _, _, timeout, tx)
 		) if timeout == APPROVAL_EXECUTION_TIMEOUT => {
-		tx.send(Ok(ValidationResult::Valid(Default::default(), Default::default()))).unwrap();
+		tx.send(Ok(ValidationResult::Valid(dummy_candidate_commitments(None), PersistedValidationData::default()))).unwrap();
 	},
 	"overseer did not receive candidate validation message",
 	);
@@ -135,8 +140,10 @@ pub async fn participation_missing_availability(ctx_handle: &mut VirtualOverseer
 async fn recover_available_data(virtual_overseer: &mut VirtualOverseer) {
 	let pov_block = PoV { block_data: BlockData(Vec::new()) };

-	let available_data =
-		AvailableData { pov: Arc::new(pov_block), validation_data: Default::default() };
+	let available_data = AvailableData {
+		pov: Arc::new(pov_block),
+		validation_data: PersistedValidationData::default(),
+	};

 	assert_matches!(
 		virtual_overseer.recv().await,
@@ -456,7 +463,7 @@ fn cast_invalid_vote_if_validation_passes_but_commitments_dont_match() {
 				// this should lead to a commitments hash mismatch
 				commitments.processed_downward_messages = 42;

-				tx.send(Ok(ValidationResult::Valid(commitments, Default::default()))).unwrap();
+				tx.send(Ok(ValidationResult::Valid(commitments, PersistedValidationData::default()))).unwrap();
 			},
 			"overseer did not receive candidate validation message",
 		);
@@ -494,7 +501,7 @@ fn cast_valid_vote_if_validation_passes() {
 			AllMessages::CandidateValidation(
 				CandidateValidationMessage::ValidateFromExhaustive(_, _, _, _, timeout, tx)
 			) if timeout == APPROVAL_EXECUTION_TIMEOUT => {
-				tx.send(Ok(ValidationResult::Valid(Default::default(), Default::default()))).unwrap();
+				tx.send(Ok(ValidationResult::Valid(dummy_candidate_commitments(None), PersistedValidationData::default()))).unwrap();
 			},
 			"overseer did not receive candidate validation message",
 		);
@@ -44,6 +44,7 @@ use sp_core::testing::TaskExecutor;
 use sp_keyring::Sr25519Keyring;
 use sp_keystore::{SyncCryptoStore, SyncCryptoStorePtr};

+use ::test_helpers::{dummy_candidate_receipt_bad_sig, dummy_digest, dummy_hash};
 use polkadot_node_subsystem::{
 	jaeger,
 	messages::{AllMessages, BlockDescription, RuntimeApiMessage, RuntimeApiRequest},
@@ -52,7 +53,8 @@ use polkadot_node_subsystem::{
 use polkadot_node_subsystem_test_helpers::{make_subsystem_context, TestSubsystemContextHandle};
 use polkadot_primitives::v1::{
 	BlakeTwo256, BlockNumber, CandidateCommitments, CandidateHash, CandidateReceipt, Hash, HashT,
-	Header, ScrapedOnChainVotes, SessionIndex, SessionInfo, ValidatorId, ValidatorIndex,
+	Header, MultiDisputeStatementSet, ScrapedOnChainVotes, SessionIndex, SessionInfo, ValidatorId,
+	ValidatorIndex,
 };

 use crate::{
@@ -179,9 +181,9 @@ impl TestState {
 		let block_header = Header {
 			parent_hash,
 			number: block_number,
-			digest: Default::default(),
-			state_root: Default::default(),
-			extrinsics_root: Default::default(),
+			digest: dummy_digest(),
+			state_root: dummy_hash(),
+			extrinsics_root: dummy_hash(),
 		};
 		let block_hash = block_header.hash();

@@ -251,7 +253,11 @@ impl TestState {
 				RuntimeApiRequest::FetchOnChainVotes(tx),
 			)) => {
 				//add some `BackedCandidates` or resolved disputes here as needed
-				tx.send(Ok(Some(ScrapedOnChainVotes::default()))).unwrap();
+				tx.send(Ok(Some(ScrapedOnChainVotes {
+					session,
+					backing_validators_per_candidate: Vec::default(),
+					disputes: MultiDisputeStatementSet::default(),
+				}))).unwrap();
 			}
 		)
 	}
@@ -358,14 +364,14 @@ async fn participation_with_distribution(
 }

 fn make_valid_candidate_receipt() -> CandidateReceipt {
-	let mut candidate_receipt = CandidateReceipt::default();
+	let mut candidate_receipt = dummy_candidate_receipt_bad_sig(dummy_hash(), dummy_hash());
 	candidate_receipt.commitments_hash = CandidateCommitments::default().hash();
 	candidate_receipt
 }

 fn make_invalid_candidate_receipt() -> CandidateReceipt {
 	// Commitments hash will be 0, which is not correct:
-	CandidateReceipt::default()
+	dummy_candidate_receipt_bad_sig(Default::default(), Some(Default::default()))
 }

 #[test]
@@ -18,3 +18,4 @@ futures-timer = "3.0.2"
 sp-application-crypto = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-keystore = { git = "https://github.com/paritytech/substrate", branch = "master" }
 polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../../primitives/test-helpers" }
@@ -1,4 +1,5 @@
 use super::*;
+use ::test_helpers::{dummy_candidate_descriptor, dummy_hash};
 use bitvec::bitvec;
 use polkadot_primitives::v1::{OccupiedCore, ScheduledCore};

@@ -10,7 +11,7 @@ pub fn occupied_core(para_id: u32) -> CoreState {
 		time_out_at: 200_u32,
 		next_up_on_time_out: None,
 		availability: bitvec![bitvec::order::Lsb0, u8; 0; 32],
-		candidate_descriptor: Default::default(),
+		candidate_descriptor: dummy_candidate_descriptor(dummy_hash()),
 		candidate_hash: Default::default(),
 	})
 }
@@ -34,13 +35,13 @@ pub fn default_bitvec(n_cores: usize) -> CoreAvailability {
 }

 pub fn scheduled_core(id: u32) -> ScheduledCore {
-	ScheduledCore { para_id: id.into(), ..Default::default() }
+	ScheduledCore { para_id: id.into(), collator: None }
 }

 mod select_availability_bitfields {
 	use super::{super::*, default_bitvec, occupied_core};
 	use futures::executor::block_on;
-	use polkadot_primitives::v1::{SigningContext, ValidatorId, ValidatorIndex};
+	use polkadot_primitives::v1::{ScheduledCore, SigningContext, ValidatorId, ValidatorIndex};
 	use sp_application_crypto::AppKey;
 	use sp_keystore::{testing::KeyStore, CryptoStore, SyncCryptoStorePtr};
 	use std::sync::Arc;
@@ -109,8 +110,11 @@ mod select_availability_bitfields {
 		let mut bitvec2 = bitvec.clone();
 		bitvec2.set(2, true);

-		let cores =
-			vec![CoreState::Free, CoreState::Scheduled(Default::default()), occupied_core(2)];
+		let cores = vec![
+			CoreState::Free,
+			CoreState::Scheduled(ScheduledCore { para_id: Default::default(), collator: None }),
+			occupied_core(2),
+		];

 		let bitfields = vec![
 			block_on(signed_bitfield(&keystore, bitvec0, ValidatorIndex(0))),
@@ -189,6 +193,7 @@ mod select_availability_bitfields {

 mod select_candidates {
 	use super::{super::*, build_occupied_core, default_bitvec, occupied_core, scheduled_core};
+	use ::test_helpers::{dummy_candidate_descriptor, dummy_hash};
 	use polkadot_node_subsystem::messages::{
 		AllMessages, RuntimeApiMessage,
 		RuntimeApiRequest::{
@@ -197,8 +202,7 @@ mod select_candidates {
 	};
 	use polkadot_node_subsystem_test_helpers::TestSubsystemSender;
 	use polkadot_primitives::v1::{
-		BlockNumber, CandidateCommitments, CandidateDescriptor, CommittedCandidateReceipt,
-		PersistedValidationData,
+		BlockNumber, CandidateCommitments, CommittedCandidateReceipt, PersistedValidationData,
 	};

 	const BLOCK_UNDER_PRODUCTION: BlockNumber = 128;
@@ -346,11 +350,10 @@ mod select_candidates {

 		let empty_hash = PersistedValidationData::<Hash, BlockNumber>::default().hash();

+		let mut descriptor_template = dummy_candidate_descriptor(dummy_hash());
+		descriptor_template.persisted_validation_data_hash = empty_hash;
 		let candidate_template = CandidateReceipt {
-			descriptor: CandidateDescriptor {
-				persisted_validation_data_hash: empty_hash,
-				..Default::default()
-			},
+			descriptor: descriptor_template,
 			commitments_hash: CandidateCommitments::default().hash(),
 		};

@@ -389,7 +392,7 @@ mod select_candidates {
 			.map(|c| BackedCandidate {
 				candidate: CommittedCandidateReceipt {
 					descriptor: c.descriptor.clone(),
-					..Default::default()
+					commitments: Default::default(),
 				},
 				validity_votes: Vec::new(),
 				validator_indices: default_bitvec(n_cores),
@@ -428,21 +431,21 @@ mod select_candidates {
 		let cores_with_code = [1, 4, 8];

 		let committed_receipts: Vec<_> = (0..mock_cores.len())
-			.map(|i| CommittedCandidateReceipt {
-				descriptor: CandidateDescriptor {
-					para_id: i.into(),
-					persisted_validation_data_hash: empty_hash,
-					..Default::default()
-				},
-				commitments: CandidateCommitments {
-					new_validation_code: if cores_with_code.contains(&i) {
-						Some(vec![].into())
-					} else {
-						None
+			.map(|i| {
+				let mut descriptor = dummy_candidate_descriptor(dummy_hash());
+				descriptor.para_id = i.into();
+				descriptor.persisted_validation_data_hash = empty_hash;
+				CommittedCandidateReceipt {
+					descriptor,
+					commitments: CandidateCommitments {
+						new_validation_code: if cores_with_code.contains(&i) {
+							Some(vec![].into())
+						} else {
+							None
+						},
+						..Default::default()
 					},
-					..Default::default()
-				},
-				..Default::default()
+				}
 			})
 			.collect();

@@ -24,3 +24,4 @@ sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures = { version = "0.3.17", features = ["thread-pool"] }
 polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 polkadot-node-primitives = { path = "../../primitives" }
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../../primitives/test-helpers" }
@@ -16,9 +16,10 @@

 use super::*;

+use ::test_helpers::{dummy_committed_candidate_receipt, dummy_validation_code};
 use futures::channel::oneshot;
 use polkadot_node_primitives::{BabeAllowedSlots, BabeEpoch, BabeEpochConfiguration};
-use polkadot_node_subsystem_test_helpers as test_helpers;
+use polkadot_node_subsystem_test_helpers::make_subsystem_context;
 use polkadot_primitives::v1::{
 	AuthorityDiscoveryId, CandidateEvent, CommittedCandidateReceipt, CoreState, GroupRotationInfo,
 	Id as ParaId, InboundDownwardMessage, InboundHrmpMessage, OccupiedCoreAssumption,
@@ -208,7 +209,7 @@ sp_api::mock_impl_runtime_apis! {

 #[test]
 fn requests_authorities() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let runtime_api = Arc::new(MockRuntimeApi::default());
 	let relay_parent = [1; 32].into();
 	let spawner = sp_core::testing::TaskExecutor::new();
@@ -234,7 +235,7 @@ fn requests_authorities() {

 #[test]
 fn requests_validators() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let runtime_api = Arc::new(MockRuntimeApi::default());
 	let relay_parent = [1; 32].into();
 	let spawner = sp_core::testing::TaskExecutor::new();
@@ -260,7 +261,7 @@ fn requests_validators() {

 #[test]
 fn requests_validator_groups() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let runtime_api = Arc::new(MockRuntimeApi::default());
 	let relay_parent = [1; 32].into();
 	let spawner = sp_core::testing::TaskExecutor::new();
@@ -286,7 +287,7 @@ fn requests_validator_groups() {

 #[test]
 fn requests_availability_cores() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let runtime_api = Arc::new(MockRuntimeApi::default());
 	let relay_parent = [1; 32].into();
 	let spawner = sp_core::testing::TaskExecutor::new();
@@ -312,7 +313,7 @@ fn requests_availability_cores() {

 #[test]
 fn requests_persisted_validation_data() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let relay_parent = [1; 32].into();
 	let para_a = 5.into();
 	let para_b = 6.into();
@@ -358,7 +359,7 @@ fn requests_persisted_validation_data() {

 #[test]
 fn requests_assumed_validation_data() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let relay_parent = [1; 32].into();
 	let para_a = 5.into();
 	let para_b = 6.into();
@@ -410,7 +411,7 @@ fn requests_assumed_validation_data() {

 #[test]
 fn requests_check_validation_outputs() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let mut runtime_api = MockRuntimeApi::default();
 	let relay_parent = [1; 32].into();
 	let para_a = 5.into();
@@ -457,7 +458,7 @@ fn requests_check_validation_outputs() {

 #[test]
 fn requests_session_index_for_child() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let runtime_api = Arc::new(MockRuntimeApi::default());
 	let relay_parent = [1; 32].into();
 	let spawner = sp_core::testing::TaskExecutor::new();
@@ -481,12 +482,26 @@ fn requests_session_index_for_child() {
 	futures::executor::block_on(future::join(subsystem_task, test_task));
 }

+fn dummy_session_info() -> SessionInfo {
+	SessionInfo {
+		validators: vec![],
+		discovery_keys: vec![],
+		assignment_keys: vec![],
+		validator_groups: vec![],
+		n_cores: 4u32,
+		zeroth_delay_tranche_width: 0u32,
+		relay_vrf_modulo_samples: 0u32,
+		n_delay_tranches: 2u32,
+		no_show_slots: 0u32,
+		needed_approvals: 1u32,
+	}
+}
 #[test]
 fn requests_session_info() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let mut runtime_api = MockRuntimeApi::default();
 	let session_index = 1;
-	runtime_api.session_info.insert(session_index, Default::default());
+	runtime_api.session_info.insert(session_index, dummy_session_info());
 	let runtime_api = Arc::new(runtime_api);
 	let spawner = sp_core::testing::TaskExecutor::new();

@@ -506,7 +521,7 @@ fn requests_session_info() {
 			})
 			.await;

-		assert_eq!(rx.await.unwrap().unwrap(), Some(Default::default()));
+		assert_eq!(rx.await.unwrap().unwrap(), Some(dummy_session_info()));

 		ctx_handle.send(FromOverseer::Signal(OverseerSignal::Conclude)).await;
 	};
@@ -516,15 +531,16 @@ fn requests_session_info() {

 #[test]
 fn requests_validation_code() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());

 	let relay_parent = [1; 32].into();
 	let para_a = 5.into();
 	let para_b = 6.into();
 	let spawner = sp_core::testing::TaskExecutor::new();
+	let validation_code = dummy_validation_code();

 	let mut runtime_api = MockRuntimeApi::default();
-	runtime_api.validation_code.insert(para_a, Default::default());
+	runtime_api.validation_code.insert(para_a, validation_code.clone());
 	let runtime_api = Arc::new(runtime_api);

 	let subsystem = RuntimeApiSubsystem::new(runtime_api.clone(), Metrics(None), spawner);
@@ -541,7 +557,7 @@ fn requests_validation_code() {
 			})
 			.await;

-		assert_eq!(rx.await.unwrap().unwrap(), Some(Default::default()));
+		assert_eq!(rx.await.unwrap().unwrap(), Some(validation_code));

 		let (tx, rx) = oneshot::channel();
 		ctx_handle
@@ -563,14 +579,17 @@ fn requests_validation_code() {

 #[test]
 fn requests_candidate_pending_availability() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let relay_parent = [1; 32].into();
 	let para_a = 5.into();
 	let para_b = 6.into();
 	let spawner = sp_core::testing::TaskExecutor::new();
+	let candidate_receipt = dummy_committed_candidate_receipt(relay_parent);

 	let mut runtime_api = MockRuntimeApi::default();
-	runtime_api.candidate_pending_availability.insert(para_a, Default::default());
+	runtime_api
+		.candidate_pending_availability
+		.insert(para_a, candidate_receipt.clone());
 	let runtime_api = Arc::new(runtime_api);

 	let subsystem = RuntimeApiSubsystem::new(runtime_api.clone(), Metrics(None), spawner);
@@ -587,7 +606,7 @@ fn requests_candidate_pending_availability() {
 			})
 			.await;

-		assert_eq!(rx.await.unwrap().unwrap(), Some(Default::default()));
+		assert_eq!(rx.await.unwrap().unwrap(), Some(candidate_receipt));

 		let (tx, rx) = oneshot::channel();

@@ -610,7 +629,7 @@ fn requests_candidate_pending_availability() {

 #[test]
 fn requests_candidate_events() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let runtime_api = Arc::new(MockRuntimeApi::default());
 	let relay_parent = [1; 32].into();
 	let spawner = sp_core::testing::TaskExecutor::new();
@@ -636,7 +655,7 @@ fn requests_candidate_events() {

 #[test]
 fn requests_dmq_contents() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());

 	let relay_parent = [1; 32].into();
 	let para_a = 5.into();
@@ -684,7 +703,7 @@ fn requests_dmq_contents() {

 #[test]
 fn requests_inbound_hrmp_channels_contents() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());

 	let relay_parent = [1; 32].into();
 	let para_a = 99.into();
@@ -741,7 +760,7 @@ fn requests_inbound_hrmp_channels_contents() {

 #[test]
 fn requests_validation_code_by_hash() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let spawner = sp_core::testing::TaskExecutor::new();

 	let (runtime_api, validation_code) = {
@@ -784,7 +803,7 @@ fn requests_validation_code_by_hash() {

 #[test]
 fn multiple_requests_in_parallel_are_working() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let runtime_api = Arc::new(MockRuntimeApi::default());
 	let relay_parent = [1; 32].into();
 	let spawner = sp_core::testing::TaskExecutor::new();
@@ -826,7 +845,7 @@ fn multiple_requests_in_parallel_are_working() {

 #[test]
 fn request_babe_epoch() {
-	let (ctx, mut ctx_handle) = test_helpers::make_subsystem_context(TaskExecutor::new());
+	let (ctx, mut ctx_handle) = make_subsystem_context(TaskExecutor::new());
 	let mut runtime_api = MockRuntimeApi::default();
 	let epoch = BabeEpoch {
 		epoch_index: 100,
@@ -29,3 +29,4 @@ sp-tracing = { git = "https://github.com/paritytech/substrate", branch = "master
 sc-network = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures-timer = "3.0.2"
 assert_matches = "1.4.0"
+polkadot-primitives-test-helpers = { path = "../../../primitives/test-helpers" }
@@ -27,6 +27,9 @@ use polkadot_primitives::v1::{
 	GroupIndex, Hash, HeadData, Id as ParaId, OccupiedCore, PersistedValidationData, SessionInfo,
 	ValidatorIndex,
 };
+use polkadot_primitives_test_helpers::{
+	dummy_collator, dummy_collator_signature, dummy_hash, dummy_validation_code,
+};

 /// Create dummy session info with two validator groups.
 pub fn make_session_info() -> SessionInfo {
@@ -114,7 +117,11 @@ impl TestCandidateBuilder {
 				pov_hash: self.pov_hash,
 				relay_parent: self.relay_parent,
 				erasure_root: self.erasure_root,
-				..Default::default()
+				collator: dummy_collator(),
+				persisted_validation_data_hash: dummy_hash(),
+				signature: dummy_collator_signature(),
+				para_head: dummy_hash(),
+				validation_code_hash: dummy_validation_code().hash(),
 			},
 			commitments: CandidateCommitments { head_data: self.head_data, ..Default::default() },
 		}
@@ -31,4 +31,5 @@ sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master
 sp-application-crypto = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sc-network = { git = "https://github.com/paritytech/substrate", branch = "master" }

-polkadot-subsystem-testhelpers = { package = "polkadot-node-subsystem-test-helpers", path = "../../subsystem-test-helpers" }
+polkadot-subsystem-test-helpers = { package = "polkadot-node-subsystem-test-helpers", path = "../../subsystem-test-helpers" }
+polkadot-primitives-test-helpers = { path = "../../../primitives/test-helpers" }
@@ -31,14 +31,15 @@ use polkadot_erasure_coding::{branches, obtain_chunks_v1 as obtain_chunks};
 use polkadot_node_primitives::{BlockData, PoV, Proof};
 use polkadot_node_subsystem_util::TimeoutExt;
 use polkadot_primitives::v1::{AuthorityDiscoveryId, HeadData, PersistedValidationData};
+use polkadot_primitives_test_helpers::{dummy_candidate_receipt, dummy_hash};
 use polkadot_subsystem::{
 	jaeger,
 	messages::{AllMessages, RuntimeApiMessage, RuntimeApiRequest},
 	ActivatedLeaf, LeafStatus,
 };
-use polkadot_subsystem_testhelpers as test_helpers;
+use polkadot_subsystem_test_helpers::{make_subsystem_context, TestSubsystemContextHandle};

-type VirtualOverseer = test_helpers::TestSubsystemContextHandle<AvailabilityRecoveryMessage>;
+type VirtualOverseer = TestSubsystemContextHandle<AvailabilityRecoveryMessage>;

 fn test_harness_fast_path<T: Future<Output = (VirtualOverseer, RequestResponseConfig)>>(
 	test: impl FnOnce(VirtualOverseer, RequestResponseConfig) -> T,
@@ -50,7 +51,7 @@ fn test_harness_fast_path<T: Future<Output = (VirtualOverseer, RequestResponseCo

 	let pool = sp_core::testing::TaskExecutor::new();

-	let (context, virtual_overseer) = test_helpers::make_subsystem_context(pool.clone());
+	let (context, virtual_overseer) = make_subsystem_context(pool.clone());

 	let (collation_req_receiver, req_cfg) = IncomingRequest::get_config_receiver();
 	let subsystem =
@@ -84,7 +85,7 @@ fn test_harness_chunks_only<T: Future<Output = (VirtualOverseer, RequestResponse

 	let pool = sp_core::testing::TaskExecutor::new();

-	let (context, virtual_overseer) = test_helpers::make_subsystem_context(pool.clone());
+	let (context, virtual_overseer) = make_subsystem_context(pool.clone());

 	let (collation_req_receiver, req_cfg) = IncomingRequest::get_config_receiver();
 	let subsystem = AvailabilityRecoverySubsystem::with_chunks_only(
@@ -118,7 +119,7 @@ macro_rules! delay {
 }

 async fn overseer_signal(
-	overseer: &mut test_helpers::TestSubsystemContextHandle<AvailabilityRecoveryMessage>,
+	overseer: &mut TestSubsystemContextHandle<AvailabilityRecoveryMessage>,
 	signal: OverseerSignal,
 ) {
 	delay!(50);
@@ -130,7 +131,7 @@ async fn overseer_signal(
 }

 async fn overseer_send(
-	overseer: &mut test_helpers::TestSubsystemContextHandle<AvailabilityRecoveryMessage>,
+	overseer: &mut TestSubsystemContextHandle<AvailabilityRecoveryMessage>,
 	msg: AvailabilityRecoveryMessage,
 ) {
 	tracing::trace!(msg = ?msg, "sending message");
@@ -142,7 +143,7 @@ async fn overseer_send(
 }

 async fn overseer_recv(
-	overseer: &mut test_helpers::TestSubsystemContextHandle<AvailabilityRecoveryMessage>,
+	overseer: &mut TestSubsystemContextHandle<AvailabilityRecoveryMessage>,
 ) -> AllMessages {
 	tracing::trace!("waiting for message ...");
 	let msg = overseer.recv().timeout(TIMEOUT).await.expect("TIMEOUT is enough to recv.");
@@ -212,7 +213,13 @@ impl TestState {
 					discovery_keys: self.validator_authority_id.clone(),
 					// all validators in the same group.
 					validator_groups: vec![(0..self.validators.len()).map(|i| ValidatorIndex(i as _)).collect()],
-					..Default::default()
+					assignment_keys: vec![],
+					n_cores: 0,
+					zeroth_delay_tranche_width: 0,
+					relay_vrf_modulo_samples: 0,
+					n_delay_tranches: 0,
+					no_show_slots: 0,
+					needed_approvals: 0,
 				}))).unwrap();
 			}
 		);
@@ -416,7 +423,7 @@ impl Default for TestState {

 		let current = Hash::repeat_byte(1);

-		let mut candidate = CandidateReceipt::default();
+		let mut candidate = dummy_candidate_receipt(dummy_hash());

 		let session_index = 10;

@@ -508,7 +515,7 @@ fn availability_is_recovered_from_chunks_if_no_group_provided() {
 		let (tx, rx) = oneshot::channel();

 		// Test another candidate, send no chunks.
-		let mut new_candidate = CandidateReceipt::default();
+		let mut new_candidate = dummy_candidate_receipt(dummy_hash());

 		new_candidate.descriptor.relay_parent = test_state.candidate.descriptor.relay_parent;

@@ -594,7 +601,7 @@ fn availability_is_recovered_from_chunks_even_if_backing_group_supplied_if_chunk
 		let (tx, rx) = oneshot::channel();

 		// Test another candidate, send no chunks.
-		let mut new_candidate = CandidateReceipt::default();
+		let mut new_candidate = dummy_candidate_receipt(dummy_hash());

 		new_candidate.descriptor.relay_parent = test_state.candidate.descriptor.relay_parent;

@@ -24,3 +24,4 @@ polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures-timer = "3"
+polkadot-primitives-test-helpers = { path = "../../../primitives/test-helpers" }
@@ -34,6 +34,7 @@ use polkadot_node_subsystem_test_helpers::{
 };
 use polkadot_node_subsystem_util::metered;
 use polkadot_primitives::v1::AuthorityDiscoveryId;
+use polkadot_primitives_test_helpers::dummy_collator_signature;
 use polkadot_subsystem::{
 	jaeger,
 	messages::{
@@ -1158,8 +1159,8 @@ fn send_messages_to_peers() {
 		{
 			let collator_protocol_message = protocol_v1::CollatorProtocolMessage::Declare(
 				Sr25519Keyring::Alice.public().into(),
-				Default::default(),
-				Default::default(),
+				0_u32.into(),
+				dummy_collator_signature(),
 			);

 			let message =
@@ -33,3 +33,4 @@ sc-network = { git = "https://github.com/paritytech/substrate", branch = "master
 parity-scale-codec = { version = "2.3.1", features = ["std"]  }

 polkadot-subsystem-testhelpers = { package = "polkadot-node-subsystem-test-helpers", path = "../../subsystem-test-helpers" }
+polkadot-primitives-test-helpers = { path = "../../../primitives/test-helpers" }
@@ -33,9 +33,10 @@ use polkadot_node_network_protocol::{our_view, request_response::IncomingRequest
 use polkadot_node_primitives::BlockData;
 use polkadot_node_subsystem_util::TimeoutExt;
 use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, CandidateDescriptor, CollatorPair, GroupRotationInfo, ScheduledCore,
-	SessionIndex, SessionInfo, ValidatorId, ValidatorIndex,
+	AuthorityDiscoveryId, CollatorPair, GroupRotationInfo, ScheduledCore, SessionIndex,
+	SessionInfo, ValidatorId, ValidatorIndex,
 };
+use polkadot_primitives_test_helpers::TestCandidateBuilder;
 use polkadot_subsystem::{
 	jaeger,
 	messages::{AllMessages, RuntimeApiMessage, RuntimeApiRequest},
@@ -43,28 +44,6 @@ use polkadot_subsystem::{
 };
 use polkadot_subsystem_testhelpers as test_helpers;

-#[derive(Default)]
-struct TestCandidateBuilder {
-	para_id: ParaId,
-	pov_hash: Hash,
-	relay_parent: Hash,
-	commitments_hash: Hash,
-}
-
-impl TestCandidateBuilder {
-	fn build(self) -> CandidateReceipt {
-		CandidateReceipt {
-			descriptor: CandidateDescriptor {
-				para_id: self.para_id,
-				pov_hash: self.pov_hash,
-				relay_parent: self.relay_parent,
-				..Default::default()
-			},
-			commitments_hash: self.commitments_hash,
-		}
-	}
-}
-
 #[derive(Clone)]
 struct TestState {
 	para_id: ParaId,
@@ -124,7 +103,13 @@ impl Default for TestState {
 				validators: validator_public,
 				discovery_keys,
 				validator_groups,
-				..Default::default()
+				assignment_keys: vec![],
+				n_cores: 0,
+				zeroth_delay_tranche_width: 0,
+				relay_vrf_modulo_samples: 0,
+				n_delay_tranches: 0,
+				no_show_slots: 0,
+				needed_approvals: 0,
 			},
 			group_rotation_info,
 			validator_peer_id,
@@ -30,8 +30,11 @@ use polkadot_node_network_protocol::{
 use polkadot_node_primitives::BlockData;
 use polkadot_node_subsystem_util::TimeoutExt;
 use polkadot_primitives::v1::{
-	CandidateDescriptor, CollatorPair, CoreState, GroupIndex, GroupRotationInfo, OccupiedCore,
-	ScheduledCore, ValidatorId, ValidatorIndex,
+	CollatorPair, CoreState, GroupIndex, GroupRotationInfo, OccupiedCore, ScheduledCore,
+	ValidatorId, ValidatorIndex,
+};
+use polkadot_primitives_test_helpers::{
+	dummy_candidate_descriptor, dummy_candidate_receipt_bad_sig, dummy_hash,
 };
 use polkadot_subsystem::messages::{AllMessages, RuntimeApiMessage, RuntimeApiRequest};
 use polkadot_subsystem_testhelpers as test_helpers;
@@ -89,7 +92,7 @@ impl Default for TestState {
 				group_responsible: GroupIndex(0),
 				candidate_hash: Default::default(),
 				candidate_descriptor: {
-					let mut d = CandidateDescriptor::default();
+					let mut d = dummy_candidate_descriptor(dummy_hash());
 					d.para_id = chain_ids[1];

 					d
@@ -551,7 +554,8 @@ fn fetch_collations_works() {
 		);

 		let pov = PoV { block_data: BlockData(vec![]) };
-		let mut candidate_a = CandidateReceipt::default();
+		let mut candidate_a =
+			dummy_candidate_receipt_bad_sig(dummy_hash(), Some(Default::default()));
 		candidate_a.descriptor.para_id = test_state.chain_ids[0];
 		candidate_a.descriptor.relay_parent = test_state.relay_parent;
 		response_channel
@@ -643,7 +647,8 @@ fn fetch_collations_works() {
 				.await;

 		let pov = PoV { block_data: BlockData(vec![1]) };
-		let mut candidate_a = CandidateReceipt::default();
+		let mut candidate_a =
+			dummy_candidate_receipt_bad_sig(dummy_hash(), Some(Default::default()));
 		candidate_a.descriptor.para_id = test_state.chain_ids[0];
 		candidate_a.descriptor.relay_parent = second;

@@ -767,7 +772,8 @@ fn fetch_next_collation_on_invalid_collation() {
 		.await;

 		let pov = PoV { block_data: BlockData(vec![]) };
-		let mut candidate_a = CandidateReceipt::default();
+		let mut candidate_a =
+			dummy_candidate_receipt_bad_sig(dummy_hash(), Some(Default::default()));
 		candidate_a.descriptor.para_id = test_state.chain_ids[0];
 		candidate_a.descriptor.relay_parent = test_state.relay_parent;
 		response_channel
@@ -30,3 +30,4 @@ sc-keystore = { git = "https://github.com/paritytech/substrate", branch = "maste
 futures-timer = "3.0.2"
 assert_matches = "1.4.0"
 lazy_static = "1.4.0"
+polkadot-primitives-test-helpers = { path = "../../../primitives/test-helpers" }
@@ -33,9 +33,10 @@ use sp_keystore::{SyncCryptoStore, SyncCryptoStorePtr};

 use polkadot_node_primitives::{DisputeMessage, SignedDisputeStatement};
 use polkadot_primitives::v1::{
-	AuthorityDiscoveryId, CandidateDescriptor, CandidateHash, CandidateReceipt, Hash, SessionIndex,
-	SessionInfo, ValidatorId, ValidatorIndex,
+	AuthorityDiscoveryId, CandidateHash, CandidateReceipt, Hash, SessionIndex, SessionInfo,
+	ValidatorId, ValidatorIndex,
 };
+use polkadot_primitives_test_helpers::dummy_candidate_descriptor;

 pub const MOCK_SESSION_INDEX: SessionIndex = 1;
 pub const MOCK_NEXT_SESSION_INDEX: SessionIndex = 2;
@@ -77,7 +78,14 @@ pub static ref MOCK_SESSION_INFO: SessionInfo =
 			.iter()
 			.map(|k| MOCK_VALIDATORS_DISCOVERY_KEYS.get(&k).unwrap().clone())
 			.collect(),
-		..Default::default()
+		assignment_keys: vec![],
+		validator_groups: vec![],
+		n_cores: 0,
+		zeroth_delay_tranche_width: 0,
+		relay_vrf_modulo_samples: 0,
+		n_delay_tranches: 0,
+		no_show_slots: 0,
+		needed_approvals: 0,
 	};

 /// `SessionInfo` for the second session. (No more validators, but two more authorities.
@@ -88,13 +96,21 @@ pub static ref MOCK_NEXT_SESSION_INFO: SessionInfo =
 				.iter()
 				.map(|k| MOCK_VALIDATORS_DISCOVERY_KEYS.get(&k).unwrap().clone())
 				.collect(),
-		..Default::default()
+		validators: vec![],
+		assignment_keys: vec![],
+		validator_groups: vec![],
+		n_cores: 0,
+		zeroth_delay_tranche_width: 0,
+		relay_vrf_modulo_samples: 0,
+		n_delay_tranches: 0,
+		no_show_slots: 0,
+		needed_approvals: 0,
 	};
 }

 pub fn make_candidate_receipt(relay_parent: Hash) -> CandidateReceipt {
 	CandidateReceipt {
-		descriptor: CandidateDescriptor { relay_parent, ..Default::default() },
+		descriptor: dummy_candidate_descriptor(relay_parent),
 		commitments_hash: Hash::random(),
 	}
 }
@@ -32,3 +32,4 @@ sp-tracing = { git = "https://github.com/paritytech/substrate", branch = "master
 sc-keystore = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sc-network = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures-timer = "3.0.2"
+polkadot-primitives-test-helpers = { path = "../../../primitives/test-helpers" }
@@ -28,7 +28,8 @@ use polkadot_node_network_protocol::{
 };
 use polkadot_node_primitives::Statement;
 use polkadot_node_subsystem_test_helpers::mock::make_ferdie_keystore;
-use polkadot_primitives::v1::{CommittedCandidateReceipt, SessionInfo, ValidationCode};
+use polkadot_primitives::v1::{SessionInfo, ValidationCode};
+use polkadot_primitives_test_helpers::{dummy_committed_candidate_receipt, dummy_hash};
 use polkadot_subsystem::{
 	jaeger,
 	messages::{RuntimeApiMessage, RuntimeApiRequest},
@@ -53,21 +54,21 @@ fn active_head_accepts_only_2_seconded_per_validator() {
 	let signing_context = SigningContext { parent_hash, session_index };

 	let candidate_a = {
-		let mut c = CommittedCandidateReceipt::default();
+		let mut c = dummy_committed_candidate_receipt(dummy_hash());
 		c.descriptor.relay_parent = parent_hash;
 		c.descriptor.para_id = 1.into();
 		c
 	};

 	let candidate_b = {
-		let mut c = CommittedCandidateReceipt::default();
+		let mut c = dummy_committed_candidate_receipt(dummy_hash());
 		c.descriptor.relay_parent = parent_hash;
 		c.descriptor.para_id = 2.into();
 		c
 	};

 	let candidate_c = {
-		let mut c = CommittedCandidateReceipt::default();
+		let mut c = dummy_committed_candidate_receipt(dummy_hash());
 		c.descriptor.relay_parent = parent_hash;
 		c.descriptor.para_id = 3.into();
 		c
@@ -369,7 +370,7 @@ fn peer_view_update_sends_messages() {
 	let hash_c = Hash::repeat_byte(3);

 	let candidate = {
-		let mut c = CommittedCandidateReceipt::default();
+		let mut c = dummy_committed_candidate_receipt(dummy_hash());
 		c.descriptor.relay_parent = hash_c;
 		c.descriptor.para_id = 1.into();
 		c
@@ -547,7 +548,7 @@ fn circulated_statement_goes_to_all_peers_with_view() {
 	let hash_c = Hash::repeat_byte(3);

 	let candidate = {
-		let mut c = CommittedCandidateReceipt::default();
+		let mut c = dummy_committed_candidate_receipt(dummy_hash());
 		c.descriptor.relay_parent = hash_b;
 		c.descriptor.para_id = 1.into();
 		c
@@ -677,7 +678,7 @@ fn receiving_from_one_sends_to_another_and_to_candidate_backing() {
 	let hash_a = Hash::repeat_byte(1);

 	let candidate = {
-		let mut c = CommittedCandidateReceipt::default();
+		let mut c = dummy_committed_candidate_receipt(dummy_hash());
 		c.descriptor.relay_parent = hash_a;
 		c.descriptor.para_id = 1.into();
 		c
@@ -864,7 +865,7 @@ fn receiving_large_statement_from_one_sends_to_another_and_to_candidate_backing(
 	let hash_b = Hash::repeat_byte(2);

 	let candidate = {
-		let mut c = CommittedCandidateReceipt::default();
+		let mut c = dummy_committed_candidate_receipt(dummy_hash());
 		c.descriptor.relay_parent = hash_a;
 		c.descriptor.para_id = 1.into();
 		c.commitments.new_validation_code = Some(ValidationCode(vec![1, 2, 3]));
@@ -1345,7 +1346,7 @@ fn share_prioritizes_backing_group() {
 	let hash_a = Hash::repeat_byte(1);

 	let candidate = {
-		let mut c = CommittedCandidateReceipt::default();
+		let mut c = dummy_committed_candidate_receipt(dummy_hash());
 		c.descriptor.relay_parent = hash_a;
 		c.descriptor.para_id = 1.into();
 		c.commitments.new_validation_code = Some(ValidationCode(vec![1, 2, 3]));
@@ -1649,7 +1650,7 @@ fn peer_cant_flood_with_large_statements() {
 	let hash_a = Hash::repeat_byte(1);

 	let candidate = {
-		let mut c = CommittedCandidateReceipt::default();
+		let mut c = dummy_committed_candidate_receipt(dummy_hash());
 		c.descriptor.relay_parent = hash_a;
 		c.descriptor.para_id = 1.into();
 		c.commitments.new_validation_code = Some(ValidationCode(vec![1, 2, 3]));
@@ -26,6 +26,7 @@ sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures = { version = "0.3.17", features = ["thread-pool"] }
 femme = "2.1.1"
 assert_matches = "1.4.0"
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../primitives/test-helpers" }

 [features]
 default = []
@@ -22,6 +22,7 @@ use futures::{channel::oneshot, pending, pin_mut, select, stream, FutureExt, Str
 use futures_timer::Delay;
 use std::time::Duration;

+use ::test_helpers::{dummy_candidate_descriptor, dummy_hash};
 use polkadot_node_primitives::{BlockData, PoV};
 use polkadot_node_subsystem_types::messages::{
 	CandidateBackingMessage, CandidateValidationMessage,
@@ -73,7 +74,7 @@ impl Subsystem1 {
 			let (tx, _) = oneshot::channel();

 			let msg = CandidateValidationMessage::ValidateFromChainState(
-				Default::default(),
+				dummy_candidate_descriptor(dummy_hash()),
 				PoV { block_data: BlockData(Vec::new()) }.into(),
 				Default::default(),
 				tx,
@@ -17,6 +17,7 @@
 use futures::{executor, pending, pin_mut, poll, select, stream, FutureExt};
 use std::{collections::HashMap, sync::atomic, task::Poll};

+use ::test_helpers::{dummy_candidate_descriptor, dummy_candidate_receipt, dummy_hash};
 use polkadot_node_network_protocol::{PeerId, UnifiedReputationChange};
 use polkadot_node_primitives::{
 	BlockData, CollationGenerationConfig, CollationResult, DisputeMessage, InvalidDisputeVote, PoV,
@@ -110,7 +111,7 @@ where
 					if c < 10 {
 						let (tx, _) = oneshot::channel();
 						ctx.send_message(CandidateValidationMessage::ValidateFromChainState(
-							Default::default(),
+							dummy_candidate_descriptor(dummy_hash()),
 							PoV { block_data: BlockData(Vec::new()) }.into(),
 							Default::default(),
 							tx,
@@ -793,9 +794,9 @@ fn test_candidate_validation_msg() -> CandidateValidationMessage {
 	let (sender, _) = oneshot::channel();
 	let pov = Arc::new(PoV { block_data: BlockData(Vec::new()) });
 	CandidateValidationMessage::ValidateFromChainState(
-		Default::default(),
+		dummy_candidate_descriptor(dummy_hash()),
 		pov,
-		Default::default(),
+		Duration::default(),
 		sender,
 	)
 }
@@ -844,7 +845,7 @@ fn test_statement_distribution_msg() -> StatementDistributionMessage {
 fn test_availability_recovery_msg() -> AvailabilityRecoveryMessage {
 	let (sender, _) = oneshot::channel();
 	AvailabilityRecoveryMessage::RecoverAvailableData(
-		Default::default(),
+		dummy_candidate_receipt(dummy_hash()),
 		Default::default(),
 		None,
 		sender,
@@ -890,7 +891,7 @@ fn test_dispute_coordinator_msg() -> DisputeCoordinatorMessage {

 fn test_dispute_distribution_msg() -> DisputeDistributionMessage {
 	let dummy_dispute_message = UncheckedDisputeMessage {
-		candidate_receipt: Default::default(),
+		candidate_receipt: dummy_candidate_receipt(dummy_hash()),
 		session_index: 0,
 		invalid_vote: InvalidDisputeVote {
 			validator_index: ValidatorIndex(0),
@@ -37,3 +37,5 @@ futures = { version = "0.3.17", features = ["thread-pool"] }
 log = "0.4.13"
 polkadot-node-subsystem-test-helpers = { path = "../subsystem-test-helpers" }
 lazy_static = "1.4.0"
+polkadot-primitives-test-helpers = { path = "../../primitives/test-helpers" }
+
@@ -25,6 +25,7 @@ use polkadot_node_subsystem::{
 };
 use polkadot_node_subsystem_test_helpers::{self as test_helpers, make_subsystem_context};
 use polkadot_primitives::v1::Hash;
+use polkadot_primitives_test_helpers::{dummy_candidate_receipt, dummy_hash};
 use std::{
 	pin::Pin,
 	sync::{
@@ -82,7 +83,7 @@ impl JobTrait for FakeCollatorProtocolJob {
 				sender
 					.send_message(CollatorProtocolMessage::Invalid(
 						Default::default(),
-						Default::default(),
+						dummy_candidate_receipt(dummy_hash()),
 					))
 					.await;
 			}
@@ -41,19 +41,9 @@ pub use polkadot_core_primitives::BlockNumber as RelayChainBlockNumber;

 /// Parachain head data included in the chain.
 #[derive(
-	PartialEq,
-	Eq,
-	Clone,
-	PartialOrd,
-	Ord,
-	Encode,
-	Decode,
-	RuntimeDebug,
-	derive_more::From,
-	TypeInfo,
-	Default,
+	PartialEq, Eq, Clone, PartialOrd, Ord, Encode, Decode, RuntimeDebug, derive_more::From, TypeInfo,
 )]
-#[cfg_attr(feature = "std", derive(Serialize, Deserialize, Hash, MallocSizeOf))]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize, Hash, MallocSizeOf, Default))]
 pub struct HeadData(#[cfg_attr(feature = "std", serde(with = "bytes"))] pub Vec<u8>);

 impl HeadData {
@@ -64,9 +54,7 @@ impl HeadData {
 }

 /// Parachain validation code.
-#[derive(
-	Default, PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug, derive_more::From, TypeInfo,
-)]
+#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug, derive_more::From, TypeInfo)]
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize, Hash, MallocSizeOf))]
 pub struct ValidationCode(#[cfg_attr(feature = "std", serde(with = "bytes"))] pub Vec<u8>);

@@ -82,7 +70,7 @@ impl ValidationCode {
 /// This type is produced by [`ValidationCode::hash`].
 ///
 /// This type makes it easy to enforce that a hash is a validation code hash on the type level.
-#[derive(Clone, Copy, Encode, Decode, Default, Hash, Eq, PartialEq, PartialOrd, Ord, TypeInfo)]
+#[derive(Clone, Copy, Encode, Decode, Hash, Eq, PartialEq, PartialOrd, Ord, TypeInfo)]
 #[cfg_attr(feature = "std", derive(MallocSizeOf))]
 pub struct ValidationCodeHash(Hash);

@@ -107,8 +107,8 @@ impl MallocSizeOf for ValidatorId {
 }

 /// Index of the validator is used as a lightweight replacement of the `ValidatorId` when appropriate.
-#[derive(Eq, Ord, PartialEq, PartialOrd, Copy, Clone, Encode, Decode, TypeInfo, Debug)]
-#[cfg_attr(feature = "std", derive(Serialize, Deserialize, Hash, MallocSizeOf))]
+#[derive(Eq, Ord, PartialEq, PartialOrd, Copy, Clone, Encode, Decode, TypeInfo)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize, Hash, MallocSizeOf, Debug))]
 pub struct ValidatorIndex(pub u32);

 // We should really get https://github.com/paritytech/polkadot/issues/2403 going ..
@@ -327,7 +327,7 @@ fn check_collator_signature<H: AsRef<[u8]>>(
 }

 /// A unique descriptor of the candidate receipt.
-#[derive(PartialEq, Eq, Clone, Encode, Decode, TypeInfo, Default)]
+#[derive(PartialEq, Eq, Clone, Encode, Decode, TypeInfo)]
 #[cfg_attr(feature = "std", derive(Debug, Hash, MallocSizeOf))]
 pub struct CandidateDescriptor<H = Hash> {
 	/// The ID of the para this is a candidate for.
@@ -370,7 +370,7 @@ impl<H: AsRef<[u8]>> CandidateDescriptor<H> {

 /// A candidate-receipt.
 #[derive(PartialEq, Eq, Clone, Encode, Decode, TypeInfo)]
-#[cfg_attr(feature = "std", derive(Debug, Default, MallocSizeOf))]
+#[cfg_attr(feature = "std", derive(Debug, MallocSizeOf))]
 pub struct CandidateReceipt<H = Hash> {
 	/// The descriptor of the candidate.
 	pub descriptor: CandidateDescriptor<H>,
@@ -395,7 +395,7 @@ impl<H> CandidateReceipt<H> {

 /// All data pertaining to the execution of a para candidate.
 #[derive(PartialEq, Eq, Clone, Encode, Decode, TypeInfo)]
-#[cfg_attr(feature = "std", derive(Debug, Default))]
+#[cfg_attr(feature = "std", derive(Debug))]
 pub struct FullCandidateReceipt<H = Hash, N = BlockNumber> {
 	/// The inner candidate receipt.
 	pub inner: CandidateReceipt<H>,
@@ -407,7 +407,7 @@ pub struct FullCandidateReceipt<H = Hash, N = BlockNumber> {
 }

 /// A candidate-receipt with commitments directly included.
-#[derive(PartialEq, Eq, Clone, Encode, Decode, TypeInfo, Default)]
+#[derive(PartialEq, Eq, Clone, Encode, Decode, TypeInfo)]
 #[cfg_attr(feature = "std", derive(Debug, Hash, MallocSizeOf))]
 pub struct CommittedCandidateReceipt<H = Hash> {
 	/// The descriptor of the candidate.
@@ -509,8 +509,8 @@ impl<H: Encode, N: Encode> PersistedValidationData<H, N> {
 }

 /// Commitments made in a `CandidateReceipt`. Many of these are outputs of validation.
-#[derive(PartialEq, Eq, Clone, Encode, Decode, TypeInfo, Default)]
-#[cfg_attr(feature = "std", derive(Debug, Hash, MallocSizeOf))]
+#[derive(PartialEq, Eq, Clone, Encode, Decode, TypeInfo)]
+#[cfg_attr(feature = "std", derive(Debug, Hash, MallocSizeOf, Default))]
 pub struct CandidateCommitments<N = BlockNumber> {
 	/// Messages destined to be interpreted by the Relay chain itself.
 	pub upward_messages: Vec<UpwardMessage>,
@@ -560,7 +560,6 @@ pub type UncheckedSignedAvailabilityBitfields = Vec<UncheckedSignedAvailabilityB

 /// A backed (or backable, depending on context) candidate.
 #[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug, TypeInfo)]
-#[cfg_attr(feature = "std", derive(Default))]
 pub struct BackedCandidate<H = Hash> {
 	/// The candidate referred to.
 	pub candidate: CommittedCandidateReceipt<H>,
@@ -669,12 +668,12 @@ impl From<u32> for GroupIndex {
 }

 /// A claim on authoring the next block for a given parathread.
-#[derive(Clone, Encode, Decode, Default, TypeInfo)]
+#[derive(Clone, Encode, Decode, TypeInfo)]
 #[cfg_attr(feature = "std", derive(PartialEq, Debug))]
 pub struct ParathreadClaim(pub Id, pub CollatorId);

 /// An entry tracking a claim to ensure it does not pass the maximum number of retries.
-#[derive(Clone, Encode, Decode, Default, TypeInfo)]
+#[derive(Clone, Encode, Decode, TypeInfo)]
 #[cfg_attr(feature = "std", derive(PartialEq, Debug))]
 pub struct ParathreadEntry {
 	/// The claim.
@@ -819,7 +818,7 @@ impl<H, N> OccupiedCore<H, N> {

 /// Information about a core which is currently occupied.
 #[derive(Clone, Encode, Decode, TypeInfo)]
-#[cfg_attr(feature = "std", derive(Debug, PartialEq, Default, MallocSizeOf))]
+#[cfg_attr(feature = "std", derive(Debug, PartialEq, MallocSizeOf))]
 pub struct ScheduledCore {
 	/// The ID of a para scheduled.
 	pub para_id: Id,
@@ -899,7 +898,7 @@ pub enum CandidateEvent<H = Hash> {

 /// Information about validator sets of a session.
 #[derive(Clone, Encode, Decode, RuntimeDebug, TypeInfo)]
-#[cfg_attr(feature = "std", derive(PartialEq, Default, MallocSizeOf))]
+#[cfg_attr(feature = "std", derive(PartialEq, MallocSizeOf))]
 pub struct SessionInfo {
 	/// Validators in canonical ordering.
 	///
@@ -949,7 +948,7 @@ pub struct SessionInfo {

 /// Scraped runtime backing votes and resolved disputes.
 #[derive(Clone, Encode, Decode, RuntimeDebug, TypeInfo)]
-#[cfg_attr(feature = "std", derive(PartialEq, Default, MallocSizeOf))]
+#[cfg_attr(feature = "std", derive(PartialEq, MallocSizeOf))]
 pub struct ScrapedOnChainVotes<H: Encode + Decode = Hash> {
 	/// The session in which the block was included.
 	pub session: SessionIndex,
@@ -0,0 +1,11 @@
+[package]
+name = "polkadot-primitives-test-helpers"
+version = "0.9.13"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2021"
+
+[dependencies]
+sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }
+sp-application-crypto = { package = "sp-application-crypto", git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
+sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "master" }
+polkadot-primitives = { path = "../" }
@@ -0,0 +1,226 @@
+// Copyright 2021 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+#![forbid(unused_crate_dependencies)]
+#![forbid(unused_extern_crates)]
+
+//! A set of primitive constructors, to aid in crafting meaningful testcase while reducing repetition.
+//!
+//! Note that `dummy_` prefixed values are meant to be fillers, that should not matter, and will
+//! contain randomness based data.
+use polkadot_primitives::v1::{
+	CandidateCommitments, CandidateDescriptor, CandidateReceipt, CollatorId, CollatorSignature,
+	CommittedCandidateReceipt, Hash, HeadData, Id as ParaId, ValidationCode, ValidationCodeHash,
+	ValidatorId,
+};
+use sp_application_crypto::sr25519;
+use sp_keyring::Sr25519Keyring;
+use sp_runtime::generic::Digest;
+
+/// Creates a candidate receipt with filler data.
+pub fn dummy_candidate_receipt<H: AsRef<[u8]>>(relay_parent: H) -> CandidateReceipt<H> {
+	CandidateReceipt::<H> {
+		commitments_hash: dummy_candidate_commitments(dummy_head_data()).hash(),
+		descriptor: dummy_candidate_descriptor(relay_parent),
+	}
+}
+
+/// Creates a committed candidate receipt with filler data.
+pub fn dummy_committed_candidate_receipt<H: AsRef<[u8]>>(
+	relay_parent: H,
+) -> CommittedCandidateReceipt<H> {
+	CommittedCandidateReceipt::<H> {
+		descriptor: dummy_candidate_descriptor::<H>(relay_parent),
+		commitments: dummy_candidate_commitments(dummy_head_data()),
+	}
+}
+
+/// Create a candidate receipt with a bogus signature and filler data. Optionally set the commitment
+/// hash with the `commitments` arg.
+pub fn dummy_candidate_receipt_bad_sig(
+	relay_parent: Hash,
+	commitments: impl Into<Option<Hash>>,
+) -> CandidateReceipt<Hash> {
+	let commitments_hash = if let Some(commitments) = commitments.into() {
+		commitments
+	} else {
+		dummy_candidate_commitments(dummy_head_data()).hash()
+	};
+	CandidateReceipt::<Hash> {
+		commitments_hash,
+		descriptor: dummy_candidate_descriptor_bad_sig(relay_parent),
+	}
+}
+
+/// Create candidate commitments with filler data.
+pub fn dummy_candidate_commitments(head_data: impl Into<Option<HeadData>>) -> CandidateCommitments {
+	CandidateCommitments {
+		head_data: head_data.into().unwrap_or(dummy_head_data()),
+		upward_messages: vec![],
+		new_validation_code: None,
+		horizontal_messages: vec![],
+		processed_downward_messages: 0,
+		hrmp_watermark: 0_u32,
+	}
+}
+
+/// Create meaningless dummy hash.
+pub fn dummy_hash() -> Hash {
+	Hash::zero()
+}
+
+/// Create meaningless dummy digest.
+pub fn dummy_digest() -> Digest {
+	Digest::default()
+}
+
+/// Create a candidate descriptor with a bogus signature and filler data.
+pub fn dummy_candidate_descriptor_bad_sig(relay_parent: Hash) -> CandidateDescriptor<Hash> {
+	let zeros = Hash::zero();
+	CandidateDescriptor::<Hash> {
+		para_id: 0.into(),
+		relay_parent,
+		collator: dummy_collator(),
+		persisted_validation_data_hash: zeros,
+		pov_hash: zeros,
+		erasure_root: zeros,
+		signature: dummy_collator_signature(),
+		para_head: zeros,
+		validation_code_hash: dummy_validation_code().hash(),
+	}
+}
+
+/// Create a candidate descriptor with filler data.
+pub fn dummy_candidate_descriptor<H: AsRef<[u8]>>(relay_parent: H) -> CandidateDescriptor<H> {
+	let collator = sp_keyring::Sr25519Keyring::Ferdie;
+	let invalid = Hash::zero();
+	let descriptor = make_valid_candidate_descriptor(
+		1.into(),
+		relay_parent,
+		invalid,
+		invalid,
+		invalid,
+		invalid,
+		invalid,
+		collator,
+	);
+	descriptor
+}
+
+/// Create meaningless validation code.
+pub fn dummy_validation_code() -> ValidationCode {
+	ValidationCode(vec![1, 2, 3])
+}
+
+/// Create meaningless head data.
+pub fn dummy_head_data() -> HeadData {
+	HeadData(vec![])
+}
+
+/// Create a meaningless collator id.
+pub fn dummy_collator() -> CollatorId {
+	CollatorId::from(sr25519::Public::from_raw([0; 32]))
+}
+
+/// Create a meaningless validator id.
+pub fn dummy_validator() -> ValidatorId {
+	ValidatorId::from(sr25519::Public::from_raw([0; 32]))
+}
+
+/// Create a meaningless collator signature.
+pub fn dummy_collator_signature() -> CollatorSignature {
+	CollatorSignature::from(sr25519::Signature([0u8; 64]))
+}
+
+/// Create a new candidate descriptor, and apply a valid signature
+/// using the provided `collator` key.
+pub fn make_valid_candidate_descriptor<H: AsRef<[u8]>>(
+	para_id: ParaId,
+	relay_parent: H,
+	persisted_validation_data_hash: Hash,
+	pov_hash: Hash,
+	validation_code_hash: impl Into<ValidationCodeHash>,
+	para_head: Hash,
+	erasure_root: Hash,
+	collator: Sr25519Keyring,
+) -> CandidateDescriptor<H> {
+	let validation_code_hash = validation_code_hash.into();
+	let payload = polkadot_primitives::v1::collator_signature_payload::<H>(
+		&relay_parent,
+		&para_id,
+		&persisted_validation_data_hash,
+		&pov_hash,
+		&validation_code_hash,
+	);
+
+	let signature = collator.sign(&payload).into();
+	let descriptor = CandidateDescriptor {
+		para_id,
+		relay_parent,
+		collator: collator.public().into(),
+		persisted_validation_data_hash,
+		pov_hash,
+		erasure_root,
+		signature,
+		para_head,
+		validation_code_hash,
+	};
+
+	assert!(descriptor.check_collator_signature().is_ok());
+	descriptor
+}
+
+/// After manually modifying the candidate descriptor, resign with a defined collator key.
+pub fn resign_candidate_descriptor_with_collator<H: AsRef<[u8]>>(
+	descriptor: &mut CandidateDescriptor<H>,
+	collator: Sr25519Keyring,
+) {
+	descriptor.collator = collator.public().into();
+	let payload = polkadot_primitives::v1::collator_signature_payload::<H>(
+		&descriptor.relay_parent,
+		&descriptor.para_id,
+		&descriptor.persisted_validation_data_hash,
+		&descriptor.pov_hash,
+		&descriptor.validation_code_hash,
+	);
+	let signature = collator.sign(&payload).into();
+	descriptor.signature = signature;
+}
+
+/// Builder for `CandidateReceipt`.
+pub struct TestCandidateBuilder {
+	pub para_id: ParaId,
+	pub pov_hash: Hash,
+	pub relay_parent: Hash,
+	pub commitments_hash: Hash,
+}
+
+impl std::default::Default for TestCandidateBuilder {
+	fn default() -> Self {
+		let zeros = Hash::zero();
+		Self { para_id: 0.into(), pov_hash: zeros, relay_parent: zeros, commitments_hash: zeros }
+	}
+}
+
+impl TestCandidateBuilder {
+	/// Build a `CandidateReceipt`.
+	pub fn build(self) -> CandidateReceipt {
+		let mut descriptor = dummy_candidate_descriptor(self.relay_parent);
+		descriptor.para_id = self.para_id;
+		descriptor.pov_hash = self.pov_hash;
+		CandidateReceipt { descriptor, commitments_hash: self.commitments_hash }
+	}
+}
@@ -59,6 +59,7 @@ pallet-treasury = { git = "https://github.com/paritytech/substrate", branch = "m
 sp-keystore = { git = "https://github.com/paritytech/substrate", branch = "master" }
 serde_json = "1.0.72"
 libsecp256k1 = "0.7.0"
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../primitives/test-helpers" }

 [features]
 default = ["std"]
@@ -543,6 +543,7 @@ mod tests {
 	use super::*;

 	use crate::{assigned_slots, mock::TestRegistrar, slots};
+	use ::test_helpers::{dummy_head_data, dummy_validation_code};
 	use frame_support::{assert_noop, assert_ok, parameter_types};
 	use frame_system::EnsureRoot;
 	use pallet_balances;
@@ -749,8 +750,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));
 			assert_ok!(TestRegistrar::<Test>::make_parachain(ParaId::from(1)));

@@ -769,8 +770,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));

 			// Register lease in current lease period
@@ -802,22 +803,22 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));

 			assert_ok!(TestRegistrar::<Test>::register(
 				2,
 				ParaId::from(2),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));

 			assert_ok!(TestRegistrar::<Test>::register(
 				3,
 				ParaId::from(3),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));

 			assert_ok!(AssignedSlots::assign_perm_parachain_slot(Origin::root(), ParaId::from(1),));
@@ -839,8 +840,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));

 			assert_eq!(AssignedSlots::permanent_slot_count(), 0);
@@ -910,8 +911,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));
 			assert_ok!(TestRegistrar::<Test>::make_parachain(ParaId::from(1)));

@@ -934,8 +935,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));

 			// Register lease in current lease period
@@ -977,8 +978,8 @@ mod tests {
 				assert_ok!(TestRegistrar::<Test>::register(
 					n,
 					ParaId::from(n as u32),
-					Default::default(),
-					Default::default()
+					dummy_head_data(),
+					dummy_validation_code()
 				));

 				assert_ok!(AssignedSlots::assign_temp_parachain_slot(
@@ -994,8 +995,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				7,
 				ParaId::from(7),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));
 			assert_noop!(
 				AssignedSlots::assign_temp_parachain_slot(
@@ -1016,8 +1017,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));

 			assert_eq!(AssignedSlots::temporary_slots(ParaId::from(1)), None);
@@ -1093,8 +1094,8 @@ mod tests {
 				assert_ok!(TestRegistrar::<Test>::register(
 					n,
 					ParaId::from(n as u32),
-					Default::default(),
-					Default::default()
+					dummy_head_data(),
+					dummy_validation_code()
 				));

 				assert_ok!(AssignedSlots::assign_temp_parachain_slot(
@@ -1216,8 +1217,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));

 			assert_ok!(AssignedSlots::assign_perm_parachain_slot(Origin::root(), ParaId::from(1),));
@@ -1242,8 +1243,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code(),
 			));

 			assert_ok!(AssignedSlots::assign_temp_parachain_slot(
@@ -655,6 +655,7 @@ impl<T: Config> Pallet<T> {
 mod tests {
 	use super::*;
 	use crate::{auctions, mock::TestRegistrar};
+	use ::test_helpers::{dummy_hash, dummy_head_data, dummy_validation_code};
 	use frame_support::{
 		assert_noop, assert_ok, assert_storage_noop,
 		dispatch::DispatchError::BadOrigin,
@@ -874,26 +875,26 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				0.into(),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				1.into(),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				2.into(),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				3.into(),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));
 		});
 		ext
@@ -1472,8 +1473,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				1337.into(),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));
 			assert_ok!(Auctions::bid(Origin::signed(1), 1337.into(), 1, 1, 4, 1));
 		});
@@ -1603,7 +1604,7 @@ mod tests {
 		new_test_ext().execute_with(|| {
 			EndingPeriod::set(30);
 			SampleLength::set(10);
-			set_last_random(Default::default(), 0);
+			set_last_random(dummy_hash(), 0);

 			assert_eq!(
 				Auctions::auction_status(System::block_number()),
@@ -1673,7 +1674,7 @@ mod tests {
 				AuctionStatus::<u32>::VrfDelay(4)
 			);

-			set_last_random(Default::default(), 45);
+			set_last_random(dummy_hash(), 45);
 			run_to_block(45);
 			assert_eq!(
 				Auctions::auction_status(System::block_number()),
@@ -828,6 +828,7 @@ mod tests {
 		mock::TestRegistrar,
 		traits::{AuctionStatus, OnSwap},
 	};
+	use ::test_helpers::{dummy_head_data, dummy_validation_code};
 	use sp_keystore::{testing::KeyStore, KeystoreExt};
 	use sp_runtime::{
 		testing::Header,
@@ -1077,8 +1078,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				para,
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));
 			return para
 		}
@@ -1220,8 +1221,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1337,
 				ParaId::from(1234),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));
 			let e = BalancesError::<Test, _>::InsufficientBalance;
 			assert_noop!(
@@ -497,6 +497,7 @@ mod tests {
 	use super::*;

 	use crate::{mock::TestRegistrar, slots};
+	use ::test_helpers::{dummy_head_data, dummy_validation_code};
 	use frame_support::{assert_noop, assert_ok, parameter_types};
 	use frame_system::EnsureRoot;
 	use pallet_balances;
@@ -628,8 +629,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));

 			assert_ok!(Slots::lease_out(1.into(), &1, 1, 1, 1));
@@ -659,8 +660,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));

 			assert_ok!(Slots::lease_out(1.into(), &1, 6, 1, 1));
@@ -702,8 +703,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));

 			assert!(Slots::lease_out(1.into(), &1, 6, 1, 1).is_ok());
@@ -752,8 +753,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));

 			assert!(Slots::lease_out(1.into(), &1, 4, 1, 1).is_ok());
@@ -787,8 +788,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));

 			assert!(Slots::lease_out(1.into(), &1, 6, 1, 1).is_ok());
@@ -830,8 +831,8 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));

 			let max_num = 5u32;
@@ -866,14 +867,14 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(2),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));

 			run_to_block(20);
@@ -897,20 +898,20 @@ mod tests {
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(1),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(2),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));
 			assert_ok!(TestRegistrar::<Test>::register(
 				1,
 				ParaId::from(3),
-				Default::default(),
-				Default::default()
+				dummy_head_data(),
+				dummy_validation_code()
 			));

 			// We will directly manipulate leases to emulate some kind of failure in the system.
@@ -16,7 +16,7 @@
 //! Autogenerated weights for `runtime_parachains::paras_inherent`
 //!
 //! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 4.0.0-dev
-//! DATE: 2021-12-02, STEPS: `50`, REPEAT: 20, LOW RANGE: `[]`, HIGH RANGE: `[]`
+//! DATE: 2021-12-10, STEPS: `50`, REPEAT: 20, LOW RANGE: `[]`, HIGH RANGE: `[]`
 //! EXECUTION: Some(Wasm), WASM-EXECUTION: Compiled, CHAIN: Some("kusama-dev"), DB CACHE: 128

 // Executed Command:
@@ -74,9 +74,9 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: Hrmp HrmpWatermarks (r:0 w:1)
 	// Storage: Paras Heads (r:0 w:1)
 	fn enter_variable_disputes(v: u32, ) -> Weight {
-		(282_901_000 as Weight)
-			// Standard Error: 13_000
-			.saturating_add((49_184_000 as Weight).saturating_mul(v as Weight))
+		(484_589_000 as Weight)
+			// Standard Error: 15_000
+			.saturating_add((49_300_000 as Weight).saturating_mul(v as Weight))
 			.saturating_add(T::DbWeight::get().reads(28 as Weight))
 			.saturating_add(T::DbWeight::get().writes(17 as Weight))
 	}
@@ -110,7 +110,7 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: Hrmp HrmpWatermarks (r:0 w:1)
 	// Storage: Paras Heads (r:0 w:1)
 	fn enter_bitfields() -> Weight {
-		(256_399_000 as Weight)
+		(459_040_000 as Weight)
 			.saturating_add(T::DbWeight::get().reads(25 as Weight))
 			.saturating_add(T::DbWeight::get().writes(16 as Weight))
 	}
@@ -136,7 +136,6 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: ParaScheduler ParathreadQueue (r:1 w:1)
 	// Storage: ParaScheduler Scheduled (r:1 w:1)
 	// Storage: ParaScheduler ValidatorGroups (r:1 w:0)
-	// Storage: Paras PastCodeMeta (r:1 w:0)
 	// Storage: Paras CurrentCodeHash (r:1 w:0)
 	// Storage: Ump RelayDispatchQueueSize (r:1 w:0)
 	// Storage: Ump NeedsDispatch (r:1 w:1)
@@ -146,10 +145,10 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: Hrmp HrmpWatermarks (r:0 w:1)
 	// Storage: Paras Heads (r:0 w:1)
 	fn enter_backed_candidates_variable(v: u32, ) -> Weight {
-		(319_740_000 as Weight)
-			// Standard Error: 26_000
-			.saturating_add((49_051_000 as Weight).saturating_mul(v as Weight))
-			.saturating_add(T::DbWeight::get().reads(29 as Weight))
+		(1_134_397_000 as Weight)
+			// Standard Error: 29_000
+			.saturating_add((49_193_000 as Weight).saturating_mul(v as Weight))
+			.saturating_add(T::DbWeight::get().reads(28 as Weight))
 			.saturating_add(T::DbWeight::get().writes(15 as Weight))
 	}
 	// Storage: ParaInherent Included (r:1 w:1)
@@ -174,8 +173,9 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: ParaScheduler ParathreadQueue (r:1 w:1)
 	// Storage: ParaScheduler Scheduled (r:1 w:1)
 	// Storage: ParaScheduler ValidatorGroups (r:1 w:0)
-	// Storage: Paras PastCodeMeta (r:1 w:0)
 	// Storage: Paras CurrentCodeHash (r:1 w:0)
+	// Storage: Paras FutureCodeHash (r:1 w:0)
+	// Storage: Paras UpgradeRestrictionSignal (r:1 w:0)
 	// Storage: Ump RelayDispatchQueueSize (r:1 w:0)
 	// Storage: Ump NeedsDispatch (r:1 w:1)
 	// Storage: Ump NextDispatchRoundStartWith (r:1 w:1)
@@ -184,8 +184,8 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: Hrmp HrmpWatermarks (r:0 w:1)
 	// Storage: Paras Heads (r:0 w:1)
 	fn enter_backed_candidate_code_upgrade() -> Weight {
-		(42_221_346_000 as Weight)
-			.saturating_add(T::DbWeight::get().reads(29 as Weight))
+		(43_202_449_000 as Weight)
+			.saturating_add(T::DbWeight::get().reads(30 as Weight))
 			.saturating_add(T::DbWeight::get().writes(15 as Weight))
 	}
 }
@@ -49,7 +49,7 @@ hex-literal = "0.3.4"
 keyring = { package = "sp-keyring", git = "https://github.com/paritytech/substrate", branch = "master" }
 frame-support-test = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sc-keystore = { git = "https://github.com/paritytech/substrate", branch = "master" }
-
+test-helpers = { package = "polkadot-primitives-test-helpers", path = "../../primitives/test-helpers"}

 [features]
 default = ["std"]
@@ -23,13 +23,13 @@ use bitvec::{order::Lsb0 as BitOrderLsb0, vec::BitVec};
 use frame_support::pallet_prelude::*;
 use primitives::v1::{
 	collator_signature_payload, AvailabilityBitfield, BackedCandidate, CandidateCommitments,
-	CandidateDescriptor, CandidateHash, CollatorId, CommittedCandidateReceipt, CompactStatement,
-	CoreIndex, CoreOccupied, DisputeStatement, DisputeStatementSet, GroupIndex, HeadData,
-	Id as ParaId, InherentData as ParachainsInherentData, InvalidDisputeStatementKind,
+	CandidateDescriptor, CandidateHash, CollatorId, CollatorSignature, CommittedCandidateReceipt,
+	CompactStatement, CoreIndex, CoreOccupied, DisputeStatement, DisputeStatementSet, GroupIndex,
+	HeadData, Id as ParaId, InherentData as ParachainsInherentData, InvalidDisputeStatementKind,
 	PersistedValidationData, SessionIndex, SigningContext, UncheckedSigned,
 	ValidDisputeStatementKind, ValidationCode, ValidatorId, ValidatorIndex, ValidityAttestation,
 };
-use sp_core::H256;
+use sp_core::{sr25519, H256};
 use sp_runtime::{
 	generic::Digest,
 	traits::{Header as HeaderT, One, Zero},
@@ -37,7 +37,7 @@ use sp_runtime::{
 };
 use sp_std::{collections::btree_map::BTreeMap, convert::TryInto, prelude::Vec, vec};

-fn dummy_validation_code() -> ValidationCode {
+fn mock_validation_code() -> ValidationCode {
 	ValidationCode(vec![1, 2, 3])
 }

@@ -47,7 +47,7 @@ fn dummy_validation_code() -> ValidationCode {
 /// "features = runtime-benchmarks".
 fn account<AccountId: Decode + Default>(name: &'static str, index: u32, seed: u32) -> AccountId {
 	let entropy = (name, index, seed).using_encoded(sp_io::hashing::blake2_256);
-	AccountId::decode(&mut &entropy[..]).unwrap_or_default()
+	AccountId::decode(&mut &entropy[..]).expect("256 bit input is valid. qed.")
 }

 /// Create a 32 byte slice based on the given number.
@@ -232,6 +232,25 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 		(para_id, core_idx, group_idx)
 	}

+	fn mock_head_data() -> HeadData {
+		let max_head_size = configuration::Pallet::<T>::config().max_head_data_size;
+		HeadData(vec![0xFF; max_head_size as usize])
+	}
+
+	fn candidate_descriptor_mock() -> CandidateDescriptor<T::Hash> {
+		CandidateDescriptor::<T::Hash> {
+			para_id: 0.into(),
+			relay_parent: Default::default(),
+			collator: CollatorId::from(sr25519::Public::from_raw([42u8; 32])),
+			persisted_validation_data_hash: Default::default(),
+			pov_hash: Default::default(),
+			erasure_root: Default::default(),
+			signature: CollatorSignature::from(sr25519::Signature([42u8; 64])),
+			para_head: Default::default(),
+			validation_code_hash: mock_validation_code().hash(),
+		}
+	}
+
 	/// Create a mock of `CandidatePendingAvailability`.
 	fn candidate_availability_mock(
 		group_idx: GroupIndex,
@@ -240,14 +259,14 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 		availability_votes: BitVec<BitOrderLsb0, u8>,
 	) -> inclusion::CandidatePendingAvailability<T::Hash, T::BlockNumber> {
 		inclusion::CandidatePendingAvailability::<T::Hash, T::BlockNumber>::new(
-			core_idx,           // core
-			candidate_hash,     // hash
-			Default::default(), // candidate descriptor
-			availability_votes, // availability votes
-			Default::default(), // backers
-			Zero::zero(),       // relay parent
-			One::one(),         // relay chain block this was backed in
-			group_idx,          // backing group
+			core_idx,                          // core
+			candidate_hash,                    // hash
+			Self::candidate_descriptor_mock(), // candidate descriptor
+			availability_votes,                // availability votes
+			Default::default(),                // backers
+			Zero::zero(),                      // relay parent
+			One::one(),                        // relay chain block this was backed in
+			group_idx,                         // backing group
 		)
 	}

@@ -269,7 +288,14 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 			candidate_hash,
 			availability_votes,
 		);
-		let commitments = CandidateCommitments::<u32>::default();
+		let commitments = CandidateCommitments::<u32> {
+			upward_messages: vec![],
+			horizontal_messages: vec![],
+			new_validation_code: None,
+			head_data: Self::mock_head_data(),
+			processed_downward_messages: 0,
+			hrmp_watermark: 0u32.into(),
+		};
 		inclusion::PendingAvailability::<T>::insert(para_id, candidate_availability);
 		inclusion::PendingAvailabilityCommitments::<T>::insert(&para_id, commitments);
 	}
@@ -315,8 +341,8 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 			paras::Pallet::<T>::schedule_para_initialize(
 				para_id,
 				paras::ParaGenesisArgs {
-					genesis_head: Default::default(),
-					validation_code: dummy_validation_code(),
+					genesis_head: Self::mock_head_data(),
+					validation_code: mock_validation_code(),
 					parachain: true,
 				},
 			)
@@ -464,7 +490,7 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 				let collator_public = CollatorId::generate_pair(None);
 				let header = Self::header(self.block_number.clone());
 				let relay_parent = header.hash();
-				let head_data: HeadData = Default::default();
+				let head_data = Self::mock_head_data();
 				let persisted_validation_data_hash = PersistedValidationData::<H256> {
 					parent_head: head_data.clone(),
 					relay_parent_number: self.relay_parent_number(),
@@ -474,7 +500,7 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 				.hash();

 				let pov_hash = Default::default();
-				let validation_code_hash = dummy_validation_code().hash();
+				let validation_code_hash = mock_validation_code().hash();
 				let payload = collator_signature_payload(
 					&relay_parent,
 					&para_id,
@@ -509,7 +535,7 @@ impl<T: paras_inherent::Config> BenchBuilder<T> {
 						upward_messages: Vec::new(),
 						horizontal_messages: Vec::new(),
 						new_validation_code: includes_code_upgrade
-							.map(|v| ValidationCode(vec![0u8; v as usize])),
+							.map(|v| ValidationCode(vec![42u8; v as usize])),
 						head_data,
 						processed_downward_messages: 0,
 						hrmp_watermark: self.relay_parent_number(),
@@ -71,7 +71,7 @@ pub(crate) enum FullCheck {

 /// A backed candidate pending availability.
 #[derive(Encode, Decode, PartialEq, TypeInfo)]
-#[cfg_attr(test, derive(Debug, Default))]
+#[cfg_attr(test, derive(Debug))]
 pub struct CandidatePendingAvailability<H, N> {
 	/// The availability core this is assigned to.
 	core: CoreIndex,
@@ -40,6 +40,10 @@ use primitives::{
 use sc_keystore::LocalKeystore;
 use sp_keystore::{SyncCryptoStore, SyncCryptoStorePtr};
 use std::sync::Arc;
+use test_helpers::{
+	dummy_candidate_descriptor, dummy_collator, dummy_collator_signature, dummy_hash,
+	dummy_validation_code,
+};

 fn default_config() -> HostConfiguration<BlockNumber> {
 	let mut config = HostConfiguration::default();
@@ -58,7 +62,7 @@ pub(crate) fn genesis_config(paras: Vec<(ParaId, bool)>) -> MockGenesisConfig {
 						id,
 						ParaGenesisArgs {
 							genesis_head: Vec::new().into(),
-							validation_code: Vec::new().into(),
+							validation_code: dummy_validation_code(),
 							parachain: is_chain,
 						},
 					)
@@ -238,7 +242,6 @@ pub(crate) async fn sign_bitfield(
 	.unwrap()
 }

-#[derive(Default)]
 pub(crate) struct TestCandidateBuilder {
 	pub(crate) para_id: ParaId,
 	pub(crate) head_data: HeadData,
@@ -251,6 +254,23 @@ pub(crate) struct TestCandidateBuilder {
 	pub(crate) hrmp_watermark: BlockNumber,
 }

+impl std::default::Default for TestCandidateBuilder {
+	fn default() -> Self {
+		let zeros = Hash::zero();
+		Self {
+			para_id: 0.into(),
+			head_data: Default::default(),
+			para_head_hash: None,
+			pov_hash: zeros,
+			relay_parent: zeros,
+			persisted_validation_data_hash: zeros,
+			new_validation_code: None,
+			validation_code: dummy_validation_code(),
+			hrmp_watermark: 0u32.into(),
+		}
+	}
+}
+
 impl TestCandidateBuilder {
 	pub(crate) fn build(self) -> CommittedCandidateReceipt {
 		CommittedCandidateReceipt {
@@ -261,7 +281,9 @@ impl TestCandidateBuilder {
 				persisted_validation_data_hash: self.persisted_validation_data_hash,
 				validation_code_hash: self.validation_code.hash(),
 				para_head: self.para_head_hash.unwrap_or_else(|| self.head_data.hash()),
-				..Default::default()
+				erasure_root: Default::default(),
+				signature: dummy_collator_signature(),
+				collator: dummy_collator(),
 			},
 			commitments: CandidateCommitments {
 				head_data: self.head_data,
@@ -388,7 +410,13 @@ fn bitfield_checks() {
 					p_id,
 					CandidatePendingAvailability {
 						availability_votes: default_availability_votes(),
-						..Default::default()
+						core: Default::default(),
+						hash: Default::default(),
+						descriptor: dummy_candidate_descriptor(dummy_hash()),
+						backers: Default::default(),
+						relay_parent_number: Default::default(),
+						backed_in_number: Default::default(),
+						backing_group: Default::default(),
 					},
 				)
 			}
@@ -339,7 +339,8 @@ mod tests {
 		new_test_ext, Configuration, Dmp, Initializer, MockGenesisConfig, Paras, SessionInfo,
 		System,
 	};
-	use primitives::v1::Id as ParaId;
+	use primitives::v1::{HeadData, Id as ParaId};
+	use test_helpers::dummy_validation_code;

 	use frame_support::{
 		assert_ok,
@@ -426,8 +427,8 @@ mod tests {

 		let mock_genesis = crate::paras::ParaGenesisArgs {
 			parachain: true,
-			genesis_head: Default::default(),
-			validation_code: Default::default(),
+			genesis_head: HeadData(vec![4, 5, 6]),
+			validation_code: dummy_validation_code(),
 		};

 		new_test_ext(MockGenesisConfig {
@@ -456,13 +456,20 @@ pub mod pallet {
 			new_code: ValidationCode,
 		) -> DispatchResult {
 			ensure_root(origin)?;
-			let prior_code_hash = <Self as Store>::CurrentCodeHash::get(&para).unwrap_or_default();
+			let maybe_prior_code_hash = <Self as Store>::CurrentCodeHash::get(&para);
 			let new_code_hash = new_code.hash();
 			Self::increase_code_ref(&new_code_hash, &new_code);
 			<Self as Store>::CurrentCodeHash::insert(&para, new_code_hash);

 			let now = frame_system::Pallet::<T>::block_number();
-			Self::note_past_code(para, now, now, prior_code_hash);
+			if let Some(prior_code_hash) = maybe_prior_code_hash {
+				Self::note_past_code(para, now, now, prior_code_hash);
+			} else {
+				log::error!(
+					"Pallet paras storage is inconsistent, prior code not found {:?}",
+					&para
+				);
+			}
 			Self::deposit_event(Event::CurrentCodeUpdated(para));
 			Ok(())
 		}
@@ -959,8 +966,13 @@ impl<T: Config> Pallet<T> {
 				<Self as Store>::UpgradeGoAheadSignal::remove(&id);

 				// Both should always be `Some` in this case, since a code upgrade is scheduled.
-				let new_code_hash = FutureCodeHash::<T>::take(&id).unwrap_or_default();
-				let prior_code_hash = CurrentCodeHash::<T>::get(&id).unwrap_or_default();
+				let new_code_hash = if let Some(new_code_hash) = FutureCodeHash::<T>::take(&id) {
+					new_code_hash
+				} else {
+					log::error!("Missing future code hash for {:?}", &id);
+					return T::DbWeight::get().reads_writes(3, 1 + 3)
+				};
+				let prior_code_hash = CurrentCodeHash::<T>::get(&id);
 				CurrentCodeHash::<T>::insert(&id, &new_code_hash);

 				let log = ConsensusLog::ParaUpgradeCode(id, new_code_hash);
@@ -969,7 +981,12 @@ impl<T: Config> Pallet<T> {
 				// `now` is only used for registering pruning as part of `fn note_past_code`
 				let now = <frame_system::Pallet<T>>::block_number();

-				let weight = Self::note_past_code(id, expected_at, now, prior_code_hash);
+				let weight = if let Some(prior_code_hash) = prior_code_hash {
+					Self::note_past_code(id, expected_at, now, prior_code_hash)
+				} else {
+					log::error!("Missing prior code hash for {:?}", &id);
+					0 as Weight
+				};

 				// add 1 to writes due to heads update.
 				weight + T::DbWeight::get().reads_writes(3, 1 + 3)
@@ -1078,6 +1095,7 @@ mod tests {
 	use super::*;
 	use frame_support::{assert_err, assert_ok};
 	use primitives::v1::BlockNumber;
+	use test_helpers::{dummy_head_data, dummy_validation_code};

 	use crate::{
 		configuration::HostConfiguration,
@@ -1195,7 +1213,7 @@ mod tests {
 					1000.into(),
 					ParaGenesisArgs {
 						parachain: false,
-						genesis_head: Default::default(),
+						genesis_head: dummy_head_data(),
 						validation_code: ValidationCode(vec![]),
 					}
 				),
@@ -1206,7 +1224,7 @@ mod tests {
 				1000.into(),
 				ParaGenesisArgs {
 					parachain: false,
-					genesis_head: Default::default(),
+					genesis_head: dummy_head_data(),
 					validation_code: ValidationCode(vec![1]),
 				}
 			));
@@ -1221,16 +1239,16 @@ mod tests {
 				0u32.into(),
 				ParaGenesisArgs {
 					parachain: true,
-					genesis_head: Default::default(),
-					validation_code: Default::default(),
+					genesis_head: dummy_head_data(),
+					validation_code: dummy_validation_code(),
 				},
 			),
 			(
 				1u32.into(),
 				ParaGenesisArgs {
 					parachain: false,
-					genesis_head: Default::default(),
-					validation_code: Default::default(),
+					genesis_head: dummy_head_data(),
+					validation_code: dummy_validation_code(),
 				},
 			),
 		];
@@ -1248,7 +1266,7 @@ mod tests {
 			let id = ParaId::from(0u32);
 			let at_block: BlockNumber = 10;
 			let included_block: BlockNumber = 12;
-			let validation_code = ValidationCode(vec![1, 2, 3]);
+			let validation_code = ValidationCode(vec![4, 5, 6]);

 			Paras::increase_code_ref(&validation_code.hash(), &validation_code);
 			<Paras as Store>::PastCodeHash::insert(&(id, at_block), &validation_code.hash());
@@ -1289,8 +1307,8 @@ mod tests {
 			0u32.into(),
 			ParaGenesisArgs {
 				parachain: true,
-				genesis_head: Default::default(),
-				validation_code: Default::default(),
+				genesis_head: dummy_head_data(),
+				validation_code: dummy_validation_code(),
 			},
 		)];

@@ -1306,7 +1324,7 @@ mod tests {
 		new_test_ext(genesis_config).execute_with(|| {
 			let id_a = ParaId::from(0u32);

-			assert_eq!(Paras::para_head(&id_a), Some(Default::default()));
+			assert_eq!(Paras::para_head(&id_a), Some(dummy_head_data()));

 			Paras::note_new_head(id_a, vec![1, 2, 3].into(), 0);

@@ -1322,16 +1340,16 @@ mod tests {
 				0u32.into(),
 				ParaGenesisArgs {
 					parachain: true,
-					genesis_head: Default::default(),
-					validation_code: Default::default(),
+					genesis_head: dummy_head_data(),
+					validation_code: dummy_validation_code(),
 				},
 			),
 			(
 				1u32.into(),
 				ParaGenesisArgs {
 					parachain: false,
-					genesis_head: Default::default(),
-					validation_code: Default::default(),
+					genesis_head: dummy_head_data(),
+					validation_code: dummy_validation_code(),
 				},
 			),
 		];
@@ -1375,7 +1393,7 @@ mod tests {
 			0u32.into(),
 			ParaGenesisArgs {
 				parachain: true,
-				genesis_head: Default::default(),
+				genesis_head: dummy_head_data(),
 				validation_code: original_code.clone(),
 			},
 		)];
@@ -1482,7 +1500,7 @@ mod tests {
 			0u32.into(),
 			ParaGenesisArgs {
 				parachain: true,
-				genesis_head: Default::default(),
+				genesis_head: dummy_head_data(),
 				validation_code: original_code.clone(),
 			},
 		)];
@@ -1570,7 +1588,7 @@ mod tests {
 			0u32.into(),
 			ParaGenesisArgs {
 				parachain: true,
-				genesis_head: Default::default(),
+				genesis_head: dummy_head_data(),
 				validation_code: vec![1, 2, 3].into(),
 			},
 		)];
@@ -1625,7 +1643,7 @@ mod tests {
 			0u32.into(),
 			ParaGenesisArgs {
 				parachain: true,
-				genesis_head: Default::default(),
+				genesis_head: dummy_head_data(),
 				validation_code: original_code.clone(),
 			},
 		)];
@@ -1808,7 +1826,7 @@ mod tests {
 			0u32.into(),
 			ParaGenesisArgs {
 				parachain: true,
-				genesis_head: Default::default(),
+				genesis_head: dummy_head_data(),
 				validation_code: vec![1, 2, 3].into(),
 			},
 		)];
@@ -49,7 +49,7 @@ use crate::{configuration, initializer::SessionChangeNotification, paras};
 pub use pallet::*;

 /// A queued parathread entry, pre-assigned to a core.
-#[derive(Encode, Decode, Default, TypeInfo)]
+#[derive(Encode, Decode, TypeInfo)]
 #[cfg_attr(test, derive(PartialEq, Debug))]
 pub struct QueuedParathread {
 	claim: ParathreadEntry,
@@ -57,7 +57,7 @@ pub struct QueuedParathread {
 }

 /// The queue of all parathread claims.
-#[derive(Encode, Decode, Default, TypeInfo)]
+#[derive(Encode, Decode, TypeInfo)]
 #[cfg_attr(test, derive(PartialEq, Debug))]
 pub struct ParathreadClaimQueue {
 	queue: Vec<QueuedParathread>,
@@ -89,6 +89,12 @@ impl ParathreadClaimQueue {
 	}
 }

+impl Default for ParathreadClaimQueue {
+	fn default() -> Self {
+		Self { queue: vec![], next_core_offset: 0 }
+	}
+}
+
 /// Reasons a core might be freed
 #[derive(Clone, Copy)]
 pub enum FreedReason {
@@ -16,7 +16,7 @@
 //! Autogenerated weights for `runtime_parachains::paras_inherent`
 //!
 //! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 4.0.0-dev
-//! DATE: 2021-12-02, STEPS: `50`, REPEAT: 20, LOW RANGE: `[]`, HIGH RANGE: `[]`
+//! DATE: 2021-12-10, STEPS: `50`, REPEAT: 20, LOW RANGE: `[]`, HIGH RANGE: `[]`
 //! EXECUTION: Some(Wasm), WASM-EXECUTION: Compiled, CHAIN: Some("polkadot-dev"), DB CACHE: 128

 // Executed Command:
@@ -69,9 +69,9 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: Hrmp HrmpWatermarks (r:0 w:1)
 	// Storage: Paras Heads (r:0 w:1)
 	fn enter_variable_disputes(v: u32, ) -> Weight {
-		(201_142_000 as Weight)
-			// Standard Error: 2_000
-			.saturating_add((304_000 as Weight).saturating_mul(v as Weight))
+		(404_051_000 as Weight)
+			// Standard Error: 4_000
+			.saturating_add((309_000 as Weight).saturating_mul(v as Weight))
 			.saturating_add(T::DbWeight::get().reads(23 as Weight))
 			.saturating_add(T::DbWeight::get().writes(14 as Weight))
 	}
@@ -102,7 +102,7 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: Hrmp HrmpWatermarks (r:0 w:1)
 	// Storage: Paras Heads (r:0 w:1)
 	fn enter_bitfields() -> Weight {
-		(248_756_000 as Weight)
+		(446_635_000 as Weight)
 			.saturating_add(T::DbWeight::get().reads(23 as Weight))
 			.saturating_add(T::DbWeight::get().writes(15 as Weight))
 	}
@@ -126,7 +126,6 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: ParaScheduler ParathreadQueue (r:1 w:1)
 	// Storage: ParaScheduler Scheduled (r:1 w:1)
 	// Storage: ParaScheduler ValidatorGroups (r:1 w:0)
-	// Storage: Paras PastCodeMeta (r:1 w:0)
 	// Storage: Paras CurrentCodeHash (r:1 w:0)
 	// Storage: Ump RelayDispatchQueueSize (r:1 w:0)
 	// Storage: Ump NeedsDispatch (r:1 w:1)
@@ -135,10 +134,10 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: Hrmp HrmpWatermarks (r:0 w:1)
 	// Storage: Paras Heads (r:0 w:1)
 	fn enter_backed_candidates_variable(v: u32, ) -> Weight {
-		(309_456_000 as Weight)
-			// Standard Error: 26_000
-			.saturating_add((49_003_000 as Weight).saturating_mul(v as Weight))
-			.saturating_add(T::DbWeight::get().reads(26 as Weight))
+		(1_103_699_000 as Weight)
+			// Standard Error: 29_000
+			.saturating_add((49_128_000 as Weight).saturating_mul(v as Weight))
+			.saturating_add(T::DbWeight::get().reads(25 as Weight))
 			.saturating_add(T::DbWeight::get().writes(14 as Weight))
 	}
 	// Storage: ParaInherent Included (r:1 w:1)
@@ -161,8 +160,9 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: ParaScheduler ParathreadQueue (r:1 w:1)
 	// Storage: ParaScheduler Scheduled (r:1 w:1)
 	// Storage: ParaScheduler ValidatorGroups (r:1 w:0)
-	// Storage: Paras PastCodeMeta (r:1 w:0)
 	// Storage: Paras CurrentCodeHash (r:1 w:0)
+	// Storage: Paras FutureCodeHash (r:1 w:0)
+	// Storage: Paras UpgradeRestrictionSignal (r:1 w:0)
 	// Storage: Ump RelayDispatchQueueSize (r:1 w:0)
 	// Storage: Ump NeedsDispatch (r:1 w:1)
 	// Storage: Ump NextDispatchRoundStartWith (r:1 w:1)
@@ -170,8 +170,8 @@ impl<T: frame_system::Config> runtime_parachains::paras_inherent::WeightInfo for
 	// Storage: Hrmp HrmpWatermarks (r:0 w:1)
 	// Storage: Paras Heads (r:0 w:1)
 	fn enter_backed_candidate_code_upgrade() -> Weight {
-		(42_288_295_000 as Weight)
-			.saturating_add(T::DbWeight::get().reads(26 as Weight))
+		(42_700_804_000 as Weight)
+			.saturating_add(T::DbWeight::get().reads(27 as Weight))
 			.saturating_add(T::DbWeight::get().writes(14 as Weight))
 	}
 }