diff --git a/polkadot/Cargo.lock b/polkadot/Cargo.lock
index 10b016a8dc..6a4606dc70 100644
--- a/polkadot/Cargo.lock
+++ b/polkadot/Cargo.lock
@@ -4342,6 +4342,7 @@ dependencies = [
  "polkadot-network-bridge",
  "polkadot-node-primitives",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-test-helpers",
  "polkadot-primitives",
  "sc-network",
  "smol 0.2.0",
@@ -4494,6 +4495,7 @@ dependencies = [
  "parking_lot 0.10.2",
  "polkadot-node-primitives",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-test-helpers",
  "polkadot-primitives",
  "sc-network",
  "sp-core",
@@ -4536,6 +4538,7 @@ dependencies = [
  "parity-scale-codec",
  "polkadot-erasure-coding",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-test-helpers",
  "polkadot-overseer",
  "polkadot-primitives",
  "sp-core",
@@ -4553,6 +4556,8 @@ dependencies = [
  "polkadot-erasure-coding",
  "polkadot-node-primitives",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-test-helpers",
+ "polkadot-node-subsystem-util",
  "polkadot-primitives",
  "polkadot-statement-table",
  "sc-client-api",
@@ -4572,6 +4577,7 @@ dependencies = [
  "futures 0.3.5",
  "log 0.4.8",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-util",
  "polkadot-primitives",
  "sc-keystore",
  "wasm-timer",
@@ -4588,6 +4594,7 @@ dependencies = [
  "parity-scale-codec",
  "polkadot-node-primitives",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-test-helpers",
  "polkadot-parachain",
  "polkadot-primitives",
  "sp-blockchain",
@@ -4602,6 +4609,7 @@ dependencies = [
  "futures 0.3.5",
  "maplit",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-test-helpers",
  "polkadot-primitives",
  "sp-blockchain",
  "sp-core",
@@ -4643,6 +4651,7 @@ dependencies = [
  "lazy_static",
  "log 0.4.8",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-util",
  "polkadot-primitives",
  "sp-core",
  "tokio 0.2.21",
@@ -4655,6 +4664,7 @@ dependencies = [
  "futures 0.3.5",
  "polkadot-node-primitives",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-test-helpers",
  "polkadot-primitives",
  "sp-api",
  "sp-blockchain",
@@ -4665,7 +4675,6 @@ dependencies = [
 name = "polkadot-node-primitives"
 version = "0.1.0"
 dependencies = [
- "async-trait",
  "parity-scale-codec",
  "polkadot-primitives",
  "polkadot-statement-table",
@@ -4687,6 +4696,51 @@ dependencies = [
  "parking_lot 0.10.2",
  "pin-project",
  "polkadot-node-primitives",
+ "polkadot-node-subsystem-test-helpers",
+ "polkadot-primitives",
+ "polkadot-statement-table",
+ "sc-network",
+ "smallvec 1.4.1",
+ "sp-core",
+]
+
+[[package]]
+name = "polkadot-node-subsystem-test-helpers"
+version = "0.1.0"
+dependencies = [
+ "async-trait",
+ "derive_more 0.99.9",
+ "futures 0.3.5",
+ "futures-timer 3.0.2",
+ "log 0.4.8",
+ "parity-scale-codec",
+ "parking_lot 0.10.2",
+ "pin-project",
+ "polkadot-node-primitives",
+ "polkadot-node-subsystem",
+ "polkadot-primitives",
+ "polkadot-statement-table",
+ "sc-network",
+ "smallvec 1.4.1",
+ "sp-core",
+]
+
+[[package]]
+name = "polkadot-node-subsystem-util"
+version = "0.1.0"
+dependencies = [
+ "assert_matches",
+ "async-trait",
+ "derive_more 0.99.9",
+ "futures 0.3.5",
+ "futures-timer 3.0.2",
+ "log 0.4.8",
+ "parity-scale-codec",
+ "parking_lot 0.10.2",
+ "pin-project",
+ "polkadot-node-primitives",
+ "polkadot-node-subsystem",
+ "polkadot-node-subsystem-test-helpers",
  "polkadot-primitives",
  "polkadot-statement-table",
  "sc-keystore",
@@ -4746,6 +4800,7 @@ dependencies = [
  "parking_lot 0.10.2",
  "polkadot-node-primitives",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-test-helpers",
  "polkadot-primitives",
  "sc-network",
  "sp-core",
@@ -5102,6 +5157,7 @@ dependencies = [
  "parking_lot 0.10.2",
  "polkadot-node-primitives",
  "polkadot-node-subsystem",
+ "polkadot-node-subsystem-test-helpers",
  "polkadot-primitives",
  "sp-core",
  "sp-keyring",
diff --git a/polkadot/Cargo.toml b/polkadot/Cargo.toml
index a56de658b3..60d2f5671d 100644
--- a/polkadot/Cargo.toml
+++ b/polkadot/Cargo.toml
@@ -61,6 +61,8 @@ members = [
 	"node/primitives",
 	"node/service",
 	"node/subsystem",
+	"node/subsystem-test-helpers",
+	"node/subsystem-util",
 	"node/test-service",
 
 	"parachain/test-parachains",
diff --git a/polkadot/node/core/av-store/Cargo.toml b/polkadot/node/core/av-store/Cargo.toml
index e89ef7a6ec..68137b6ae7 100644
--- a/polkadot/node/core/av-store/Cargo.toml
+++ b/polkadot/node/core/av-store/Cargo.toml
@@ -19,6 +19,6 @@ derive_more = "0.99.9"
 [dev-dependencies]
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures = { version = "0.3.5", features = ["thread-pool"] }
-polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem", features = [ "test-helpers" ] }
+polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 kvdb-memorydb = "0.7.0"
 assert_matches = "1.3.0"
diff --git a/polkadot/node/core/av-store/src/lib.rs b/polkadot/node/core/av-store/src/lib.rs
index 14f027dc86..9c33052afc 100644
--- a/polkadot/node/core/av-store/src/lib.rs
+++ b/polkadot/node/core/av-store/src/lib.rs
@@ -316,7 +316,7 @@ mod tests {
 		AvailableData, BlockData, HeadData, GlobalValidationData, LocalValidationData, PoV,
 		OmittedValidationData,
 	};
-	use polkadot_subsystem::test_helpers;
+	use polkadot_node_subsystem_test_helpers as test_helpers;
 
 	struct TestHarness {
 		virtual_overseer: test_helpers::TestSubsystemContextHandle<AvailabilityStoreMessage>,
diff --git a/polkadot/node/core/backing/Cargo.toml b/polkadot/node/core/backing/Cargo.toml
index 22f8dcc734..9401290f2b 100644
--- a/polkadot/node/core/backing/Cargo.toml
+++ b/polkadot/node/core/backing/Cargo.toml
@@ -13,6 +13,7 @@ keystore = { package = "sc-keystore", git = "https://github.com/paritytech/subst
 polkadot-primitives = { path = "../../../primitives" }
 polkadot-node-primitives = { path = "../../primitives" }
 polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem" }
+polkadot-node-subsystem-util = { path = "../../subsystem-util" }
 erasure-coding = { package = "polkadot-erasure-coding", path = "../../../erasure-coding" }
 statement-table = { package = "polkadot-statement-table", path = "../../../statement-table" }
 derive_more = "0.99.9"
@@ -24,4 +25,4 @@ sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures = { version = "0.3.5", features = ["thread-pool"] }
 assert_matches = "1.3.0"
-polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem", features = [ "test-helpers" ] }
+polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
diff --git a/polkadot/node/core/backing/src/lib.rs b/polkadot/node/core/backing/src/lib.rs
index f7608f0d0f..a77d98cd23 100644
--- a/polkadot/node/core/backing/src/lib.rs
+++ b/polkadot/node/core/backing/src/lib.rs
@@ -45,14 +45,14 @@ use polkadot_subsystem::{
 		ProvisionerMessage, RuntimeApiMessage, StatementDistributionMessage, ValidationFailed,
 		RuntimeApiRequest,
 	},
-	util::{
-		self,
-		request_session_index_for_child,
-		request_validator_groups,
-		request_validators,
-		request_from_runtime,
-		Validator,
-	},
+};
+use polkadot_node_subsystem_util::{
+	self as util,
+	request_session_index_for_child,
+	request_validator_groups,
+	request_validators,
+	request_from_runtime,
+	Validator,
 	delegated_subsystem,
 };
 use statement_table::{
@@ -896,13 +896,13 @@ mod tests {
 	}
 
 	struct TestHarness {
-		virtual_overseer: polkadot_subsystem::test_helpers::TestSubsystemContextHandle<CandidateBackingMessage>,
+		virtual_overseer: polkadot_node_subsystem_test_helpers::TestSubsystemContextHandle<CandidateBackingMessage>,
 	}
 
 	fn test_harness<T: Future<Output=()>>(keystore: KeyStorePtr, test: impl FnOnce(TestHarness) -> T) {
 		let pool = sp_core::testing::TaskExecutor::new();
 
-		let (context, virtual_overseer) = polkadot_subsystem::test_helpers::make_subsystem_context(pool.clone());
+		let (context, virtual_overseer) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool.clone());
 
 		let subsystem = CandidateBackingSubsystem::run(context, keystore, pool.clone());
 
@@ -960,7 +960,7 @@ mod tests {
 
 	// Tests that the subsystem performs actions that are requied on startup.
 	async fn test_startup(
-		virtual_overseer: &mut polkadot_subsystem::test_helpers::TestSubsystemContextHandle<CandidateBackingMessage>,
+		virtual_overseer: &mut polkadot_node_subsystem_test_helpers::TestSubsystemContextHandle<CandidateBackingMessage>,
 		test_state: &TestState,
 	) {
 		// Start work on some new parent.
diff --git a/polkadot/node/core/bitfield-signing/Cargo.toml b/polkadot/node/core/bitfield-signing/Cargo.toml
index b8a6cedcc5..11bfef713c 100644
--- a/polkadot/node/core/bitfield-signing/Cargo.toml
+++ b/polkadot/node/core/bitfield-signing/Cargo.toml
@@ -11,5 +11,6 @@ futures = "0.3.5"
 log = "0.4.8"
 polkadot-primitives = { path = "../../../primitives" }
 polkadot-node-subsystem = { path = "../../subsystem" }
+polkadot-node-subsystem-util = { path = "../../subsystem-util" }
 keystore = { package = "sc-keystore", git = "https://github.com/paritytech/substrate", branch = "master" }
 wasm-timer = "0.2.4"
diff --git a/polkadot/node/core/bitfield-signing/src/lib.rs b/polkadot/node/core/bitfield-signing/src/lib.rs
index 4e409a2576..feca8f0c8f 100644
--- a/polkadot/node/core/bitfield-signing/src/lib.rs
+++ b/polkadot/node/core/bitfield-signing/src/lib.rs
@@ -29,7 +29,9 @@ use polkadot_node_subsystem::{
 		BitfieldSigningMessage, CandidateBackingMessage, RuntimeApiMessage,
 	},
 	errors::RuntimeApiError,
-	util::{self, JobManager, JobTrait, ToJobTrait, Validator},
+};
+use polkadot_node_subsystem_util::{
+	self as util, JobManager, JobTrait, ToJobTrait, Validator
 };
 use polkadot_primitives::v1::{AvailabilityBitfield, CoreState, Hash, ValidatorIndex};
 use std::{convert::TryFrom, pin::Pin, time::Duration};
diff --git a/polkadot/node/core/candidate-validation/Cargo.toml b/polkadot/node/core/candidate-validation/Cargo.toml
index 3c36b16758..8f1b7a0fa0 100644
--- a/polkadot/node/core/candidate-validation/Cargo.toml
+++ b/polkadot/node/core/candidate-validation/Cargo.toml
@@ -21,4 +21,4 @@ log = "0.4.8"
 sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures = { version = "0.3.5", features = ["thread-pool"] }
 assert_matches = "1.3.0"
-polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem", features = ["test-helpers"] }
+polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
diff --git a/polkadot/node/core/candidate-validation/src/lib.rs b/polkadot/node/core/candidate-validation/src/lib.rs
index 8dcc0a574b..f12f6b1b9d 100644
--- a/polkadot/node/core/candidate-validation/src/lib.rs
+++ b/polkadot/node/core/candidate-validation/src/lib.rs
@@ -470,7 +470,7 @@ fn validate_candidate_exhaustive<B: ValidationBackend, S: SpawnNamed + 'static>(
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use polkadot_subsystem::test_helpers;
+	use polkadot_node_subsystem_test_helpers as test_helpers;
 	use polkadot_primitives::v1::{HeadData, BlockData};
 	use sp_core::testing::TaskExecutor;
 	use futures::executor;
diff --git a/polkadot/node/core/chain-api/Cargo.toml b/polkadot/node/core/chain-api/Cargo.toml
index 61ca313e33..d626a0d932 100644
--- a/polkadot/node/core/chain-api/Cargo.toml
+++ b/polkadot/node/core/chain-api/Cargo.toml
@@ -13,5 +13,5 @@ polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsys
 [dev-dependencies]
 futures = { version = "0.3.5", features = ["thread-pool"] }
 maplit = "1.0.2"
-polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem", features = ["test-helpers"] }
+polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
diff --git a/polkadot/node/core/chain-api/src/lib.rs b/polkadot/node/core/chain-api/src/lib.rs
index a9e93ca9dd..20213e3c08 100644
--- a/polkadot/node/core/chain-api/src/lib.rs
+++ b/polkadot/node/core/chain-api/src/lib.rs
@@ -121,7 +121,7 @@ mod tests {
 	use futures::{future::BoxFuture, channel::oneshot};
 
 	use polkadot_primitives::v1::{Hash, BlockNumber, BlockId, Header};
-	use polkadot_subsystem::test_helpers::{make_subsystem_context, TestSubsystemContextHandle};
+	use polkadot_node_subsystem_test_helpers::{make_subsystem_context, TestSubsystemContextHandle};
 	use sp_blockchain::Info as BlockInfo;
 	use sp_core::testing::TaskExecutor;
 
diff --git a/polkadot/node/core/provisioner/Cargo.toml b/polkadot/node/core/provisioner/Cargo.toml
index 6c6477c904..c391f8e45a 100644
--- a/polkadot/node/core/provisioner/Cargo.toml
+++ b/polkadot/node/core/provisioner/Cargo.toml
@@ -11,6 +11,7 @@ futures = "0.3.5"
 log = "0.4.8"
 polkadot-primitives = { path = "../../../primitives" }
 polkadot-node-subsystem = { path = "../../subsystem" }
+polkadot-node-subsystem-util = { path = "../../subsystem-util" }
 
 [dev-dependencies]
 lazy_static = "1.4"
diff --git a/polkadot/node/core/provisioner/src/lib.rs b/polkadot/node/core/provisioner/src/lib.rs
index 712c1a834f..9a92858a9e 100644
--- a/polkadot/node/core/provisioner/src/lib.rs
+++ b/polkadot/node/core/provisioner/src/lib.rs
@@ -25,16 +25,17 @@ use futures::{
 	prelude::*,
 };
 use polkadot_node_subsystem::{
-	delegated_subsystem,
 	errors::{ChainApiError, RuntimeApiError},
 	messages::{
 		AllMessages, ChainApiMessage, ProvisionableData, ProvisionerInherentData,
 		ProvisionerMessage, RuntimeApiMessage,
 	},
-	util::{
-		self, request_availability_cores, request_global_validation_data,
-		request_local_validation_data, JobTrait, ToJobTrait,
-	},
+};
+use polkadot_node_subsystem_util::{
+	self as util,
+	delegated_subsystem,
+	request_availability_cores, request_global_validation_data,
+	request_local_validation_data, JobTrait, ToJobTrait,
 };
 use polkadot_primitives::v1::{
 	validation_data_hash, BackedCandidate, BlockNumber, CoreState, Hash, OccupiedCoreAssumption,
diff --git a/polkadot/node/core/runtime-api/Cargo.toml b/polkadot/node/core/runtime-api/Cargo.toml
index 7dfde63947..229366627a 100644
--- a/polkadot/node/core/runtime-api/Cargo.toml
+++ b/polkadot/node/core/runtime-api/Cargo.toml
@@ -16,4 +16,4 @@ polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsys
 [dev-dependencies]
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 futures = { version = "0.3.5", features = ["thread-pool"] }
-polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem", features = ["test-helpers"] }
+polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
diff --git a/polkadot/node/core/runtime-api/src/lib.rs b/polkadot/node/core/runtime-api/src/lib.rs
index 34d73f91ec..9b93bb914b 100644
--- a/polkadot/node/core/runtime-api/src/lib.rs
+++ b/polkadot/node/core/runtime-api/src/lib.rs
@@ -123,7 +123,7 @@ mod tests {
 		Id as ParaId, OccupiedCoreAssumption, LocalValidationData, SessionIndex, ValidationCode,
 		CommittedCandidateReceipt, CandidateEvent,
 	};
-	use polkadot_subsystem::test_helpers;
+	use polkadot_node_subsystem_test_helpers as test_helpers;
 	use sp_core::testing::TaskExecutor;
 
 	use std::collections::HashMap;
diff --git a/polkadot/node/network/bitfield-distribution/Cargo.toml b/polkadot/node/network/bitfield-distribution/Cargo.toml
index 2addbbfd3f..bf7d23a900 100644
--- a/polkadot/node/network/bitfield-distribution/Cargo.toml
+++ b/polkadot/node/network/bitfield-distribution/Cargo.toml
@@ -18,7 +18,7 @@ polkadot-network = { path = "../../../network" }
 sc-network = { git = "https://github.com/paritytech/substrate", branch = "master" }
 
 [dev-dependencies]
-polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem", features = [ "test-helpers" ] }
+polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 bitvec = { version = "0.17.4", default-features = false, features = ["alloc"] }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
 parking_lot = "0.10.0"
diff --git a/polkadot/node/network/bitfield-distribution/src/lib.rs b/polkadot/node/network/bitfield-distribution/src/lib.rs
index 66f9ca9509..d67b5e353f 100644
--- a/polkadot/node/network/bitfield-distribution/src/lib.rs
+++ b/polkadot/node/network/bitfield-distribution/src/lib.rs
@@ -607,7 +607,7 @@ mod test {
 	use futures::executor;
 	use maplit::hashmap;
 	use polkadot_primitives::v1::{Signed, ValidatorPair, AvailabilityBitfield};
-	use polkadot_subsystem::test_helpers::make_subsystem_context;
+	use polkadot_node_subsystem_test_helpers::make_subsystem_context;
 	use smol_timeout::TimeoutExt;
 	use sp_core::crypto::Pair;
 	use std::time::Duration;
diff --git a/polkadot/node/network/bridge/Cargo.toml b/polkadot/node/network/bridge/Cargo.toml
index 3e405d3d75..ef8b605bb1 100644
--- a/polkadot/node/network/bridge/Cargo.toml
+++ b/polkadot/node/network/bridge/Cargo.toml
@@ -19,5 +19,5 @@ polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsys
 [dev-dependencies]
 assert_matches = "1.3.0"
 parking_lot = "0.10.0"
-polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem", features = [ "test-helpers" ] }
+polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
diff --git a/polkadot/node/network/bridge/src/lib.rs b/polkadot/node/network/bridge/src/lib.rs
index 56117732f9..85063b2b0c 100644
--- a/polkadot/node/network/bridge/src/lib.rs
+++ b/polkadot/node/network/bridge/src/lib.rs
@@ -521,7 +521,7 @@ mod tests {
 	use assert_matches::assert_matches;
 
 	use polkadot_subsystem::messages::{StatementDistributionMessage, BitfieldDistributionMessage};
-	use polkadot_subsystem::test_helpers::{SingleItemSink, SingleItemStream};
+	use polkadot_node_subsystem_test_helpers::{SingleItemSink, SingleItemStream};
 
 	// The subsystem's view of the network - only supports a single call to `event_stream`.
 	struct TestNetwork {
@@ -540,7 +540,7 @@ mod tests {
 		TestNetwork,
 		TestNetworkHandle,
 	) {
-		let (net_tx, net_rx) = polkadot_subsystem::test_helpers::single_item_sink();
+		let (net_tx, net_rx) = polkadot_node_subsystem_test_helpers::single_item_sink();
 		let (action_tx, action_rx) = mpsc::unbounded();
 
 		(
@@ -621,13 +621,13 @@ mod tests {
 
 	struct TestHarness {
 		network_handle: TestNetworkHandle,
-		virtual_overseer: polkadot_subsystem::test_helpers::TestSubsystemContextHandle<NetworkBridgeMessage>,
+		virtual_overseer: polkadot_node_subsystem_test_helpers::TestSubsystemContextHandle<NetworkBridgeMessage>,
 	}
 
 	fn test_harness<T: Future<Output=()>>(test: impl FnOnce(TestHarness) -> T) {
 		let pool = sp_core::testing::TaskExecutor::new();
 		let (network, network_handle) = new_test_network();
-		let (context, virtual_overseer) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (context, virtual_overseer) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		let network_bridge = run_network(
 			network,
diff --git a/polkadot/node/network/pov-distribution/Cargo.toml b/polkadot/node/network/pov-distribution/Cargo.toml
index c6bfd4b14c..74a566f35d 100644
--- a/polkadot/node/network/pov-distribution/Cargo.toml
+++ b/polkadot/node/network/pov-distribution/Cargo.toml
@@ -20,4 +20,4 @@ polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsys
 parking_lot = "0.10.0"
 assert_matches = "1.3.0"
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
-polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem", features = [ "test-helpers" ] }
+polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
diff --git a/polkadot/node/network/pov-distribution/src/lib.rs b/polkadot/node/network/pov-distribution/src/lib.rs
index 4409d7f1ea..9589e2fad9 100644
--- a/polkadot/node/network/pov-distribution/src/lib.rs
+++ b/polkadot/node/network/pov-distribution/src/lib.rs
@@ -639,7 +639,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 		let mut descriptor = CandidateDescriptor::default();
 		descriptor.pov_hash = pov_hash;
 
@@ -719,7 +719,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 		let mut descriptor = CandidateDescriptor::default();
 		descriptor.pov_hash = pov_hash;
 
@@ -797,7 +797,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			handle_network_update(
@@ -869,7 +869,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			// Peer A answers our request before peer B.
@@ -957,7 +957,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			// Peer A answers our request: right relay parent, awaited hash, wrong PoV.
@@ -1020,7 +1020,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			// Peer A answers our request: right relay parent, awaited hash, wrong PoV.
@@ -1081,7 +1081,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			// Peer A answers our request: right relay parent, awaited hash, wrong PoV.
@@ -1139,7 +1139,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			let max_plausibly_awaited = n_validators * 2;
@@ -1224,7 +1224,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			let pov_hash = make_pov(vec![1, 2, 3]).hash();
@@ -1286,7 +1286,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			let pov_hash = make_pov(vec![1, 2, 3]).hash();
@@ -1363,7 +1363,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			handle_network_update(
@@ -1446,7 +1446,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			handle_network_update(
diff --git a/polkadot/node/network/statement-distribution/Cargo.toml b/polkadot/node/network/statement-distribution/Cargo.toml
index 04e6def40e..6dfaee78bb 100644
--- a/polkadot/node/network/statement-distribution/Cargo.toml
+++ b/polkadot/node/network/statement-distribution/Cargo.toml
@@ -21,7 +21,7 @@ indexmap = "1.4.0"
 
 [dev-dependencies]
 parking_lot = "0.10.0"
-polkadot-subsystem = { package = "polkadot-node-subsystem", path = "../../subsystem", features = ["test-helpers"] }
+polkadot-node-subsystem-test-helpers = { path = "../../subsystem-test-helpers" }
 assert_matches = "1.3.0"
 sp-keyring = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
diff --git a/polkadot/node/network/statement-distribution/src/lib.rs b/polkadot/node/network/statement-distribution/src/lib.rs
index 5cc67cfea0..f58e6da4d4 100644
--- a/polkadot/node/network/statement-distribution/src/lib.rs
+++ b/polkadot/node/network/statement-distribution/src/lib.rs
@@ -1235,7 +1235,7 @@ mod tests {
 		};
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 		let peer = PeerId::random();
 
 		executor::block_on(async move {
@@ -1327,7 +1327,7 @@ mod tests {
 		].into_iter().collect();
 
 		let pool = sp_core::testing::TaskExecutor::new();
-		let (mut ctx, mut handle) = polkadot_subsystem::test_helpers::make_subsystem_context(pool);
+		let (mut ctx, mut handle) = polkadot_node_subsystem_test_helpers::make_subsystem_context(pool);
 
 		executor::block_on(async move {
 			let statement = {
diff --git a/polkadot/node/primitives/Cargo.toml b/polkadot/node/primitives/Cargo.toml
index df288438a8..b38e7e542e 100644
--- a/polkadot/node/primitives/Cargo.toml
+++ b/polkadot/node/primitives/Cargo.toml
@@ -10,5 +10,4 @@ polkadot-primitives = { path = "../../primitives" }
 polkadot-statement-table = { path = "../../statement-table" }
 parity-scale-codec = { version = "1.3.4", default-features = false, features = ["derive"] }
 runtime_primitives = { package = "sp-runtime", git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
-async-trait = "0.1"
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
diff --git a/polkadot/node/subsystem-test-helpers/Cargo.toml b/polkadot/node/subsystem-test-helpers/Cargo.toml
new file mode 100644
index 0000000000..105e6b5816
--- /dev/null
+++ b/polkadot/node/subsystem-test-helpers/Cargo.toml
@@ -0,0 +1,23 @@
+[package]
+name = "polkadot-node-subsystem-test-helpers"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+description = "Subsystem traits and message definitions"
+
+[dependencies]
+async-trait = "0.1"
+derive_more = "0.99.9"
+futures = "0.3.5"
+futures-timer = "3.0.2"
+log = "0.4.8"
+parity-scale-codec = "1.3.4"
+parking_lot = "0.10.0"
+pin-project = "0.4.22"
+polkadot-node-primitives = { path = "../primitives" }
+polkadot-node-subsystem = { path = "../subsystem" }
+polkadot-primitives = { path = "../../primitives" }
+polkadot-statement-table = { path = "../../statement-table" }
+sc-network = { git = "https://github.com/paritytech/substrate", branch = "master" }
+smallvec = "1.4.1"
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
diff --git a/polkadot/node/subsystem/src/test_helpers.rs b/polkadot/node/subsystem-test-helpers/src/lib.rs
similarity index 97%
rename from polkadot/node/subsystem/src/test_helpers.rs
rename to polkadot/node/subsystem-test-helpers/src/lib.rs
index 256a928b43..a4070c028c 100644
--- a/polkadot/node/subsystem/src/test_helpers.rs
+++ b/polkadot/node/subsystem-test-helpers/src/lib.rs
@@ -16,8 +16,8 @@
 
 //! Utilities for testing subsystems.
 
-use crate::{SubsystemContext, FromOverseer, SubsystemResult, SubsystemError};
-use crate::messages::AllMessages;
+use polkadot_node_subsystem::{SubsystemContext, FromOverseer, SubsystemResult, SubsystemError};
+use polkadot_node_subsystem::messages::AllMessages;
 
 use futures::prelude::*;
 use futures::channel::mpsc;
diff --git a/polkadot/node/subsystem-util/Cargo.toml b/polkadot/node/subsystem-util/Cargo.toml
new file mode 100644
index 0000000000..6ed2999213
--- /dev/null
+++ b/polkadot/node/subsystem-util/Cargo.toml
@@ -0,0 +1,32 @@
+[package]
+name = "polkadot-node-subsystem-util"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+description = "Subsystem traits and message definitions"
+
+[dependencies]
+async-trait = "0.1"
+derive_more = "0.99.9"
+futures = "0.3.5"
+futures-timer = "3.0.2"
+keystore = { package = "sc-keystore", git = "https://github.com/paritytech/substrate", branch = "master" }
+log = "0.4.8"
+parity-scale-codec = "1.3.4"
+parking_lot = { version = "0.10.0", optional = true }
+pin-project = "0.4.22"
+polkadot-node-primitives = { path = "../primitives" }
+polkadot-node-subsystem = { path = "../subsystem" }
+polkadot-primitives = { path = "../../primitives" }
+polkadot-statement-table = { path = "../../statement-table" }
+sc-network = { git = "https://github.com/paritytech/substrate", branch = "master" }
+smallvec = "1.4.1"
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
+streamunordered = "0.5.1"
+
+[dev-dependencies]
+assert_matches = "1.3.0"
+async-trait = "0.1"
+futures = { version = "0.3.5", features = ["thread-pool"] }
+parking_lot = "0.10.0"
+polkadot-node-subsystem-test-helpers = { path = "../subsystem-test-helpers" }
diff --git a/polkadot/node/subsystem/src/util.rs b/polkadot/node/subsystem-util/src/lib.rs
similarity index 94%
rename from polkadot/node/subsystem/src/util.rs
rename to polkadot/node/subsystem-util/src/lib.rs
index 7472ebeb8a..cc8cbd239d 100644
--- a/polkadot/node/subsystem/src/util.rs
+++ b/polkadot/node/subsystem-util/src/lib.rs
@@ -20,7 +20,7 @@
 //! or determining what their validator ID is. These common interests are factored into
 //! this module.
 
-use crate::{
+use polkadot_node_subsystem::{
 	errors::{ChainApiError, RuntimeApiError},
 	messages::{AllMessages, RuntimeApiMessage, RuntimeApiRequest, RuntimeApiSender},
 	FromOverseer, SpawnedSubsystem, Subsystem, SubsystemContext, SubsystemError, SubsystemResult,
@@ -43,7 +43,7 @@ use polkadot_primitives::v1::{
 	SessionIndex, Signed, SigningContext, ValidationCode, ValidatorId, ValidatorIndex,
 	ValidatorPair,
 };
-use sp_core::Pair;
+use sp_core::{Pair, traits::SpawnNamed};
 use std::{
 	collections::HashMap,
 	convert::{TryFrom, TryInto},
@@ -53,10 +53,15 @@ use std::{
 };
 use streamunordered::{StreamUnordered, StreamYield};
 
-/// This reexport is required so that external crates can use the `delegated_subsystem` macro properly.
-///
-/// Otherwise, downstream crates might have to modify their `Cargo.toml` to ensure `sp-core` appeared there.
-pub use sp_core::traits::SpawnNamed;
+/// These reexports are required so that external crates can use the `delegated_subsystem` macro properly.
+pub mod reexports {
+	pub use sp_core::traits::SpawnNamed;
+	pub use polkadot_node_subsystem::{
+		SpawnedSubsystem,
+		Subsystem,
+		SubsystemContext,
+	};
+}
 
 /// Duration a job will wait after sending a stop signal before hard-aborting.
 pub const JOB_GRACEFUL_STOP_DURATION: Duration = Duration::from_secs(1);
@@ -655,9 +660,9 @@ where
 		run_args: &Job::RunArgs,
 		err_tx: &mut Option<mpsc::Sender<(Option<Hash>, JobsError<Job::Error>)>>,
 	) -> bool {
-		use crate::ActiveLeavesUpdate;
-		use crate::FromOverseer::{Communication, Signal};
-		use crate::OverseerSignal::{ActiveLeaves, BlockFinalized, Conclude};
+		use polkadot_node_subsystem::ActiveLeavesUpdate;
+		use polkadot_node_subsystem::FromOverseer::{Communication, Signal};
+		use polkadot_node_subsystem::OverseerSignal::{ActiveLeaves, BlockFinalized, Conclude};
 
 		match incoming {
 			Ok(Signal(ActiveLeaves(ActiveLeavesUpdate {
@@ -783,7 +788,7 @@ where
 /// It is possible to create a type which implements `Subsystem` by simply doing:
 ///
 /// ```ignore
-/// pub type ExampleSubsystem<Spawner, Context> = util::JobManager<Spawner, Context, ExampleJob>;
+/// pub type ExampleSubsystem<Spawner, Context> = JobManager<Spawner, Context, ExampleJob>;
 /// ```
 ///
 /// However, doing this requires that job itself and all types which comprise it (i.e. `ToJob`, `FromJob`, `Error`, `RunArgs`)
@@ -791,7 +796,7 @@ where
 /// can reduce the total number of public types exposed, i.e.
 ///
 /// ```ignore
-/// type Manager<Spawner, Context> = util::JobManager<Spawner, Context, ExampleJob>;
+/// type Manager<Spawner, Context> = JobManager<Spawner, Context, ExampleJob>;
 /// pub struct ExampleSubsystem {
 /// 	manager: Manager<Spawner, Context>,
 /// }
@@ -820,7 +825,7 @@ macro_rules! delegated_subsystem {
 	($job:ident($run_args:ty) <- $to_job:ty as $subsystem:ident; $subsystem_name:expr) => {
 		#[doc = "Manager type for the "]
 		#[doc = $subsystem_name]
-		type Manager<Spawner, Context> = $crate::util::JobManager<Spawner, Context, $job>;
+		type Manager<Spawner, Context> = $crate::JobManager<Spawner, Context, $job>;
 
 		#[doc = "An implementation of the "]
 		#[doc = $subsystem_name]
@@ -830,15 +835,15 @@ macro_rules! delegated_subsystem {
 
 		impl<Spawner, Context> $subsystem<Spawner, Context>
 		where
-			Spawner: Clone + $crate::util::SpawnNamed + Send + Unpin,
-			Context: $crate::SubsystemContext,
-			<Context as $crate::SubsystemContext>::Message: Into<$to_job>,
+			Spawner: Clone + $crate::reexports::SpawnNamed + Send + Unpin,
+			Context: $crate::reexports::SubsystemContext,
+			<Context as $crate::reexports::SubsystemContext>::Message: Into<$to_job>,
 		{
 			#[doc = "Creates a new "]
 			#[doc = $subsystem_name]
 			pub fn new(spawner: Spawner, run_args: $run_args) -> Self {
 				$subsystem {
-					manager: $crate::util::JobManager::new(spawner, run_args)
+					manager: $crate::JobManager::new(spawner, run_args)
 				}
 			}
 
@@ -848,13 +853,13 @@ macro_rules! delegated_subsystem {
 			}
 		}
 
-		impl<Spawner, Context> $crate::Subsystem<Context> for $subsystem<Spawner, Context>
+		impl<Spawner, Context> $crate::reexports::Subsystem<Context> for $subsystem<Spawner, Context>
 		where
-			Spawner: $crate::util::SpawnNamed + Send + Clone + Unpin + 'static,
-			Context: $crate::SubsystemContext,
-			<Context as $crate::SubsystemContext>::Message: Into<$to_job>,
+			Spawner: $crate::reexports::SpawnNamed + Send + Clone + Unpin + 'static,
+			Context: $crate::reexports::SubsystemContext,
+			<Context as $crate::reexports::SubsystemContext>::Message: Into<$to_job>,
 		{
-			fn start(self, ctx: Context) -> $crate::SpawnedSubsystem {
+			fn start(self, ctx: Context) -> $crate::reexports::SpawnedSubsystem {
 				self.manager.start(ctx)
 			}
 		}
@@ -863,10 +868,9 @@ macro_rules! delegated_subsystem {
 
 #[cfg(test)]
 mod tests {
-	use crate::{
+	use super::{Error as UtilError, JobManager, JobTrait, JobsError, ToJobTrait};
+	use polkadot_node_subsystem::{
 		messages::{AllMessages, CandidateSelectionMessage},
-		test_helpers::{self, make_subsystem_context},
-		util::{self, JobManager, JobTrait, JobsError, ToJobTrait},
 		ActiveLeavesUpdate, FromOverseer, OverseerSignal, SpawnedSubsystem, Subsystem,
 	};
 	use assert_matches::assert_matches;
@@ -878,6 +882,7 @@ mod tests {
 	};
 	use futures_timer::Delay;
 	use polkadot_primitives::v1::Hash;
+	use polkadot_node_subsystem_test_helpers::{self as test_helpers, make_subsystem_context};
 	use std::{collections::HashMap, convert::TryFrom, pin::Pin, time::Duration};
 
 	// basic usage: in a nutshell, when you want to define a subsystem, just focus on what its jobs do;
@@ -941,13 +946,13 @@ mod tests {
 	// we include it in the RunArgs
 	#[derive(Clone)]
 	enum FromJob {
-		Test(String),
+		Test,
 	}
 
 	impl From<FromJob> for AllMessages {
 		fn from(from_job: FromJob) -> AllMessages {
 			match from_job {
-				FromJob::Test(s) => AllMessages::Test(s),
+				FromJob::Test => AllMessages::CandidateSelection(CandidateSelectionMessage::default()),
 			}
 		}
 	}
@@ -1054,10 +1059,9 @@ mod tests {
 	fn starting_and_stopping_job_works() {
 		let relay_parent: Hash = [0; 32].into();
 		let mut run_args = HashMap::new();
-		let test_message = format!("greetings from {}", relay_parent);
 		run_args.insert(
 			relay_parent.clone(),
-			vec![FromJob::Test(test_message.clone())],
+			vec![FromJob::Test],
 		);
 
 		test_harness(run_args, |mut overseer_handle, err_rx| async move {
@@ -1068,7 +1072,7 @@ mod tests {
 				.await;
 			assert_matches!(
 				overseer_handle.recv().await,
-				AllMessages::Test(msg) if msg == test_message
+				AllMessages::CandidateSelection(_)
 			);
 			overseer_handle
 				.send(FromOverseer::Signal(OverseerSignal::ActiveLeaves(
@@ -1098,7 +1102,7 @@ mod tests {
 			assert_eq!(errs[0].0, Some(relay_parent));
 			assert_matches!(
 				errs[0].1,
-				JobsError::Utility(util::Error::JobNotFound(match_relay_parent)) if relay_parent == match_relay_parent
+				JobsError::Utility(UtilError::JobNotFound(match_relay_parent)) if relay_parent == match_relay_parent
 			);
 		});
 	}
diff --git a/polkadot/node/subsystem/Cargo.toml b/polkadot/node/subsystem/Cargo.toml
index f924808182..3e676cb4f1 100644
--- a/polkadot/node/subsystem/Cargo.toml
+++ b/polkadot/node/subsystem/Cargo.toml
@@ -10,7 +10,6 @@ async-trait = "0.1"
 derive_more = "0.99.9"
 futures = "0.3.5"
 futures-timer = "3.0.2"
-keystore = { package = "sc-keystore", git = "https://github.com/paritytech/substrate", branch = "master" }
 log = "0.4.8"
 parity-scale-codec = "1.3.4"
 parking_lot = { version = "0.10.0", optional = true }
@@ -21,13 +20,10 @@ polkadot-statement-table = { path = "../../statement-table" }
 sc-network = { git = "https://github.com/paritytech/substrate", branch = "master" }
 smallvec = "1.4.1"
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
-streamunordered = "0.5.1"
 
 [dev-dependencies]
 assert_matches = "1.3.0"
 async-trait = "0.1"
 futures = { version = "0.3.5", features = ["thread-pool"] }
 parking_lot = "0.10.0"
-
-[features]
-test-helpers = [ "parking_lot" ]
+polkadot-node-subsystem-test-helpers = { path = "../subsystem-test-helpers" }
diff --git a/polkadot/node/subsystem/src/lib.rs b/polkadot/node/subsystem/src/lib.rs
index 7e112f5439..3f72e2f269 100644
--- a/polkadot/node/subsystem/src/lib.rs
+++ b/polkadot/node/subsystem/src/lib.rs
@@ -36,9 +36,6 @@ use crate::messages::AllMessages;
 
 pub mod errors;
 pub mod messages;
-pub mod util;
-#[cfg(any(test, feature = "test-helpers"))]
-pub mod test_helpers;
 
 /// How many slots are stack-reserved for active leaves updates
 ///
diff --git a/polkadot/node/subsystem/src/messages.rs b/polkadot/node/subsystem/src/messages.rs
index 29014c55a8..acc41a2e7f 100644
--- a/polkadot/node/subsystem/src/messages.rs
+++ b/polkadot/node/subsystem/src/messages.rs
@@ -61,6 +61,12 @@ impl CandidateSelectionMessage {
 	}
 }
 
+impl Default for CandidateSelectionMessage {
+	fn default() -> Self {
+		CandidateSelectionMessage::Invalid(Default::default(), Default::default())
+	}
+}
+
 /// Messages received by the Candidate Backing subsystem.
 #[derive(Debug)]
 pub enum CandidateBackingMessage {
@@ -509,10 +515,4 @@ pub enum AllMessages {
 	NetworkBridge(NetworkBridgeMessage),
 	/// Message for the Chain API subsystem
 	ChainApi(ChainApiMessage),
-	/// Test message
-	///
-	/// This variant is only valid while testing, but makes the process of testing the
-	/// subsystem job manager much simpler.
-	#[cfg(test)]
-	Test(String),
 }