Child storage tests and genesis fix. (#3185)

* Using child storage, (srml-support only), test failing .

* fix simple tests.

* Enumerable by requiring owned struct (previous form only allow
&'static).
Broken tests are from genesis init.

* implement for_child_keys_with_prefix

* indent

* clear_child_prefix fix.

* clear_child_prefix fix 2.

* fix for storage_impl, if/when allowing child and not child this could be
reverted.

* Fix lot of urlinked child genesis, still need to look upon actual
genesis srml module code.
Probably still a lot of broken code needing debugging.

* switch well_known_key to their associated module child trie.
Fix a genesis init (balance).
Complete some testing.
Comment some tests before using.

* fixing test runtime child keys

* latest commit fix broken genesis init

* fix system balances child name.

* Important fix: storage_root from test externalities need children (it is
already the case for ext).

* executive root with child calculation

* Avoid empty trie on test ext.

* Symetric removal of key for system.

* commenting changes related tests.

* Remove child module specifics.

* fix issues.

* fix some formatting

* fix bench and bump runtime

* Remove extend_storage_overlays, assimilate_storage do the same as is
proper considering srml macro.

* Fix warning for assimilate.

* Removing kill as they do not impact any test cases.

* Use tuple of storage map instead of two parameters. This changes the
behavior of decl_storage genesis build closure (breaking api).

* Do not use build storage before assimilate.

* fix error

* Update core/state-machine/src/backend.rs

substrate/core/test-runtime/src/genesismap.rs

@@ -21,7 +21,7 @@ use runtime_io::{blake2_256, twox_128};
 use super::{AuthorityId, AccountId, WASM_BINARY};
 use codec::{Encode, KeyedVec, Joiner};
 use primitives::{ChangesTrieConfiguration, map, storage::well_known_keys};
-use sr_primitives::traits::Block;
+use sr_primitives::traits::{Block as BlockT, Hash as HashT, Header as HeaderT};
 
 /// Configuration of a general Substrate test genesis block.
 pub struct GenesisConfig {
@@ -50,7 +50,10 @@ impl GenesisConfig {
 		}
 	}
 
-	pub fn genesis_map(&self) -> HashMap<Vec<u8>, Vec<u8>> {
+	pub fn genesis_map(&self) -> (
+		HashMap<Vec<u8>, Vec<u8>>,
+		HashMap<Vec<u8>, HashMap<Vec<u8>, Vec<u8>>>,
+	) {
 		let wasm_runtime = WASM_BINARY.to_vec();
 		let mut map: HashMap<Vec<u8>, Vec<u8>> = self.balances.iter()
 			.map(|&(ref account, balance)| (account.to_keyed_vec(b"balance:"), vec![].and(&balance)))
@@ -67,10 +70,32 @@ impl GenesisConfig {
 			map.insert(well_known_keys::CHANGES_TRIE_CONFIG.to_vec(), changes_trie_config.encode());
 		}
 		map.insert(twox_128(&b"sys:auth"[..])[..].to_vec(), self.authorities.encode());
-		map
+		(map, Default::default())
 	}
 }
 
+pub fn insert_genesis_block(
+	storage: &mut (
+		HashMap<Vec<u8>, Vec<u8>>,
+		HashMap<Vec<u8>, HashMap<Vec<u8>, Vec<u8>>>,
+	)
+) -> primitives::hash::H256 {
+
+	let child_roots = storage.1.iter().map(|(sk, child_map)| {
+		let state_root = <<<crate::Block as BlockT>::Header as HeaderT>::Hashing as HashT>::trie_root(
+			child_map.clone().into_iter()
+		);
+		(sk.clone(), state_root.encode())
+	});
+	let state_root = <<<crate::Block as BlockT>::Header as HeaderT>::Hashing as HashT>::trie_root(
+		storage.0.clone().into_iter().chain(child_roots)
+	);
+	let block: crate::Block = substrate_client::genesis::construct_genesis_block(state_root);
+	let genesis_hash = block.header.hash();
+	storage.0.extend(additional_storage_with_genesis(&block));
+	genesis_hash
+}
+
 pub fn additional_storage_with_genesis(genesis_block: &crate::Block) -> HashMap<Vec<u8>, Vec<u8>> {
 	map![
 		twox_128(&b"latest"[..]).to_vec() => genesis_block.hash().as_fixed_bytes().to_vec()