test-runtime: GenesisBuilder runtime API impl + tests (#14310)

* test-runtime: GenesisBuilder runtime API impl + tests

This PR provides implementation of `GenesisBuilder` API for `substrate-test-runtime`, can be considered as reference imiplementation for other runtimes.
The `GenesisBuilder` implementation is gated by `gensis-config` feature.

Tested scenarios:
- default `GenesisConfig` to JSON blob,
- deserialization of `GenesisConfig` from custom JSON, and storing its keys into the Storage (genesis storage creation).
- creation of genesis storage using partial JSON definition,
- checking if invalid/renamed JSON files causes the runtime to panic,

* missing file added

* client: GenesisBuilder helper added

* feature renamed: genesis-config -> genesis-builder

* Update Cargo.toml

* Update Cargo.toml

* Update Cargo.toml

* Update Cargo.toml

* redundant function removed

* genesis builder helper: introduced RuntimeGenesisBuild

* test-runtime: get rid of unused T

* redundant bound removed

* helper: use GenesisBuild again

* tests adjusted for on_genesis

* test-runtime: support for BuildGenesisConfig

* helper: BuildGenesisConfig support

* Update client/genesis-builder/src/lib.rs

Co-authored-by: Davide Galassi <davxy@datawok.net>

* Update test-utils/runtime/src/test_json/readme.md

Co-authored-by: Davide Galassi <davxy@datawok.net>

* Update test-utils/runtime/src/test_json/readme.md

Co-authored-by: Davide Galassi <davxy@datawok.net>

* Update test-utils/runtime/src/genesismap.rs

Co-authored-by: Davide Galassi <davxy@datawok.net>

* jsons are now human-friendly

* fix

* improvements

* jsons fixed

* helper: no_defaults added

* test-runtime: no_defaults added

* test-runtime: patching fn removed

* helper: patching fn removed

* helper: moved to frame_support

* test-runtime: fixes

* Cargo.lock updated

* fmt + naming

* test-runtime: WasmExecutor used

* helper / test-runtime: struct removed

* test-runtime: merge fixes

* Cargo.lock + test-utils/runtime/Cargo.toml updated

* doc fixed

* client/rpc: test fixed (new rt api)

* client/rpc-spec-v2: test fix

* doc fix

* test-runtime: disable-genesis-builder feature

* fix

* fix

* ".git/.scripts/commands/fmt/fmt.sh"

* test-runtime: rerun added to build script

---------

Co-authored-by: Davide Galassi <davxy@datawok.net>
Co-authored-by: parity-processbot <>

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

@@ -73,10 +73,10 @@ impl Default for GenesisStorageBuilder {
 }
 
 impl GenesisStorageBuilder {
-	/// Creates a storage builder for genesis config. `substrage test runtime` `GenesisConfig` is
-	/// initialized with provided `authorities`, `endowed_accounts` with given balance. Key-pairs
-	/// from `extra_storage` will be injected into built storage. `HEAP_PAGES` key and value will
-	/// also be placed into storage.
+	/// Creates a storage builder for genesis config. `substrage test runtime`
+	/// [`RuntimeGenesisConfig`] is initialized with provided `authorities`, `endowed_accounts` with
+	/// given balance. Key-value pairs from `extra_storage` will be injected into built storage.
+	/// `HEAP_PAGES` key and value will also be placed into storage.
 	pub fn new(
 		authorities: Vec<AccountId>,
 		endowed_accounts: Vec<AccountId>,
@@ -91,7 +91,7 @@ impl GenesisStorageBuilder {
 		}
 	}
 
-	/// Override default wasm code to be placed into GenesisConfig.
+	/// Override default wasm code to be placed into RuntimeGenesisConfig.
 	pub fn with_wasm_code(mut self, wasm_code: &Option<Vec<u8>>) -> Self {
 		self.wasm_code = wasm_code.clone();
 		self
@@ -107,8 +107,8 @@ impl GenesisStorageBuilder {
 		self
 	}
 
-	/// Builds the `GenesisConfig` and returns its storage.
-	pub fn build(self) -> Storage {
+	/// A `RuntimeGenesisConfig` from internal configuration
+	pub fn genesis_config(&self) -> RuntimeGenesisConfig {
 		let authorities_sr25519: Vec<_> = self
 			.authorities
 			.clone()
@@ -116,7 +116,7 @@ impl GenesisStorageBuilder {
 			.map(|id| sr25519::Public::from(id))
 			.collect();
 
-		let genesis_config = RuntimeGenesisConfig {
+		RuntimeGenesisConfig {
 			system: frame_system::GenesisConfig {
 				code: self.wasm_code.clone().unwrap_or(wasm_binary_unwrap().to_vec()),
 				..Default::default()
@@ -135,11 +135,15 @@ impl GenesisStorageBuilder {
 				..Default::default()
 			},
 			balances: pallet_balances::GenesisConfig { balances: self.balances.clone() },
-		};
+		}
+	}
 
-		let mut storage = genesis_config
+	/// Builds the `RuntimeGenesisConfig` and returns its storage.
+	pub fn build(self) -> Storage {
+		let mut storage = self
+			.genesis_config()
 			.build_storage()
-			.expect("Build storage from substrate-test-runtime GenesisConfig");
+			.expect("Build storage from substrate-test-runtime RuntimeGenesisConfig");
 
 		if let Some(heap_pages) = self.heap_pages_override {
 			storage.top.insert(well_known_keys::HEAP_PAGES.into(), heap_pages.encode());