Dump genesis to JSON file (#218)

* Merge remote-tracking branch 'origin/master' into gav-xts-dont-panic

* Update wasm.

* consensus, session and staking all panic-safe.

* Democracy doesn't panic in apply.

* Fix tests.

* Extra helper macro, council depanicked.

* Fix one test.

* Fix up all council tests. No panics!

* Council voting depanicked.

* Dispatch returns result.

* session & staking tests updated

* Fix democracy tests.

* Fix council tests.

* Fix up polkadot parachains in runtime

* Fix borked merge

* More Slicable support

Support general `Option` and array types.

* Basic storage types.

* Existential deposit for contract creation

* Basic implemnetation along with removals

* Fix tests.

* externalities builder fix.

* Tests.

* Fix up the runtime.

* Fix tests.

* Add generic `Address` type.

* Initial function integration of Address into Extrinsic.

* Fix build

* All tests compile.

* Fix (some) tests.

* Fix signing.

* Push error.

* transfer can accept Address

* Make Address generic over AccountIndex

* Fix test

* Make Council use Address for dispatch.

* Fix build

* Bend over backwards to support braindead derive.

* Repot some files.

* Fix tests.

* Fix grumbles

* Remove Default bound

* Fix build for new nightly.

* Make `apply_extrinsic` never panic, return useful Result.

* More merge hell

* Doesn't build, but might do soon

* Serde woes

* get substrate-runtime-staking compiling

* Polkadot builds again!

* Fix all build.

* Fix tests & binaries.

* Reserve some extra initial byte values of address for future format changes

* Make semantic of `ReservedBalance` clear.

* Fix panic handler.

* Integrate other balance transformations into the new model

Fix up staking tests.

* Fix runtime tests.

* Fix panic build.

* Tests for demonstrating interaction between balance types.

* Repot some runtime code

* Fix checkedblock in non-std builds

* Get rid of `DoLookup` phantom.

* Attempt to make transaction_pool work with lookups.

* Remove vscode settings

* New attempt at making transaction pool work.

* It builds again!

* --all builds

* Fix tests.

* New build.

* Test account nonce reset.

* polkadot transaction pool tests/framework.

* Initial draft (working).

* Address grumbles.

* Revert bad `map_or`

* Rebuild binaries, workaround.

* Avoid checking in vscode

* reconnecting, shared, slog

* CLI options for name and telemetry url

* ensure telemetry url imples enabled

* Avoid casting to usize early.

* Provide on-connect event for session message

* Better port

* heartbeat and some renaming

* transaction pool stuff

* minor renaming.

* report telemetry

* cleanups.

* Fix for previous cleanup

* dump genesis, dev mode, renaming

* Rework chain spec/config &c. to allow for genesis file loading.

* Avoid producing genesis storage when unneeded

* Allow reading JSON genesis state dumps

* tests work again

* better logging.

* Fix wasm build.

* Introduce PoC-1 spec

* Made block message compatible with poc-1

* Squashed changes for dumping genesis block.

* Binaries.

* Made block message compatible with poc-1

* Remove dead code.

* Fix bad merge.

* Argument passing and returning values when invoking sandboxed funcs (#189)

* Fixed block download sequence (#223)

* Trie-based execution proof (#177)

* TrieBasedBackend

* trie tests

* redunant return_value removed

* use Trie::get_with to record trie proofs

* Relaying tx/blocks by light clients (#190)

* do not import external transactions into light tx pool

* do not announce blocks on light clients

* blocks_are_not_announced_by_light_nodes

substrate/polkadot/api/src/full.rs

@@ -187,10 +187,10 @@ impl<B: LocalBackend<Block>> LocalPolkadotApi for Client<B, LocalCallExecutor<B,
 mod tests {
 	use super::*;
 	use keyring::Keyring;
-	use client::{self, LocalCallExecutor};
+	use client::LocalCallExecutor;
 	use client::in_mem::Backend as InMemory;
 	use substrate_executor::NativeExecutionDispatch;
-	use runtime::{GenesisConfig, ConsensusConfig, SessionConfig, BuildExternalities};
+	use runtime::{GenesisConfig, ConsensusConfig, SessionConfig, BuildStorage};
 
 	fn validators() -> Vec<AccountId> {
 		vec![
@@ -207,33 +207,23 @@ mod tests {
 	}
 
 	fn client() -> Client<InMemory<Block>, LocalCallExecutor<InMemory<Block>, NativeExecutor<LocalDispatch>>, Block> {
-		struct GenesisBuilder;
+		let genesis_config = GenesisConfig {
+			consensus: Some(ConsensusConfig {
+				code: LocalDispatch::native_equivalent().to_vec(),
+				authorities: session_keys(),
+			}),
+			system: None,
+			session: Some(SessionConfig {
+				validators: validators(),
+				session_length: 100,
+			}),
+			council: Some(Default::default()),
+			democracy: Some(Default::default()),
+			parachains: Some(Default::default()),
+			staking: Some(Default::default()),
+		};
 
-		impl client::GenesisBuilder<Block> for GenesisBuilder {
-			fn build(self) -> (Header, Vec<(Vec<u8>, Vec<u8>)>) {
-				let genesis_config = GenesisConfig {
-					consensus: Some(ConsensusConfig {
-						code: LocalDispatch::native_equivalent().to_vec(),
-						authorities: session_keys(),
-					}),
-					system: None,
-					session: Some(SessionConfig {
-						validators: validators(),
-						session_length: 100,
-					}),
-					council: Some(Default::default()),
-					democracy: Some(Default::default()),
-					parachains: Some(Default::default()),
-					staking: Some(Default::default()),
-				};
-
-				let storage = genesis_config.build_externalities();
-				let block = ::client::genesis::construct_genesis_block::<Block>(&storage);
-				(block.header, storage.into_iter().collect())
-			}
-		}
-
-		::client::new_in_mem(LocalDispatch::new(), GenesisBuilder).unwrap()
+		::client::new_in_mem(LocalDispatch::new(), genesis_config.build_storage()).unwrap()
 	}
 
 	#[test]