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/srml/generic-asset/src/lib.rs

@@ -479,12 +479,11 @@ decl_storage! {
 		config(endowed_accounts): Vec<T::AccountId>;
 
 		build(|
-			storage: &mut sr_primitives::StorageOverlay,
-			_: &mut sr_primitives::ChildrenStorageOverlay,
+			storage: &mut (sr_primitives::StorageOverlay, sr_primitives::ChildrenStorageOverlay),
 			config: &GenesisConfig<T>| {
 			config.assets.iter().for_each(|asset_id| {
 				config.endowed_accounts.iter().for_each(|account_id| {
-					storage.insert(
+					storage.0.insert(
 						<FreeBalance<T>>::key_for(asset_id, account_id),
 						<T::Balance as codec::Encode>::encode(&config.initial_balance)
 					);

substrate/srml/generic-asset/src/mock.rs

@@ -20,7 +20,11 @@
 
 #![cfg(test)]
 
-use sr_primitives::{Perbill, testing::Header, traits::{BlakeTwo256, IdentityLookup}};
+use sr_primitives::{
+	Perbill,
+	testing::Header,
+	traits::{BlakeTwo256, IdentityLookup},
+};
 use primitives::{Blake2Hasher, H256};
 use support::{parameter_types, impl_outer_event, impl_outer_origin};
 
@@ -114,10 +118,9 @@ impl ExtBuilder {
 
 	// builds genesis config
 	pub fn build(self) -> runtime_io::TestExternalities<Blake2Hasher> {
-		let mut t = system::GenesisConfig::default().build_storage::<Test>().unwrap().0;
+		let mut t = system::GenesisConfig::default().build_storage::<Test>().unwrap();
 
-		t.extend(
-			GenesisConfig::<Test> {
+		GenesisConfig::<Test> {
 				assets: vec![self.asset_id],
 				endowed_accounts: self.accounts,
 				initial_balance: self.initial_balance,
@@ -125,10 +128,7 @@ impl ExtBuilder {
 				staking_asset_id: 16000,
 				spending_asset_id: 16001,
 			}
-			.build_storage()
-			.unwrap()
-			.0,
-		);
+			.assimilate_storage(&mut t).unwrap();
 
 		t.into()
 	}
@@ -140,6 +140,5 @@ pub fn new_test_ext() -> runtime_io::TestExternalities<Blake2Hasher> {
 	system::GenesisConfig::default()
 		.build_storage::<Test>()
 		.unwrap()
-		.0
 		.into()
 }