Improve and unify testing facilities (#1844)

* Improve and unify testing facilities

This improves the testing facilities by making the test client easier to
use. It also removes code that is not required for the test client.
Besides that it also moves the test service and test client under
`node/test`.

* Update Cargo.lock

* Update node/test/client/src/block_builder.rs

Co-authored-by: Andronik Ordian <write@reusable.software>

* Remove explicit lifetime annotation

* Fix warnings and add extra `BlockBuilderExt`

Co-authored-by: Andronik Ordian <write@reusable.software>

polkadot/node/service/src/grandpa_support.rs

@@ -232,37 +232,29 @@ pub(crate) fn kusama_hard_forks() -> Vec<(
 #[cfg(test)]
 mod tests {
 	use grandpa::VotingRule;
-	use polkadot_test_runtime_client::prelude::*;
-	use polkadot_test_runtime_client::sp_consensus::BlockOrigin;
-	use sc_block_builder::BlockBuilderProvider;
+	use polkadot_test_client::{
+		TestClientBuilder, TestClientBuilderExt, DefaultTestClientBuilderExt, InitPolkadotBlockBuilder,
+		ClientBlockImportExt,
+	};
 	use sp_blockchain::HeaderBackend;
-	use sp_runtime::generic::BlockId;
-	use sp_runtime::traits::Header;
+	use sp_runtime::{generic::BlockId, traits::Header};
+	use consensus_common::BlockOrigin;
 	use std::sync::Arc;
 
 	#[test]
 	fn grandpa_pause_voting_rule_works() {
 		let _ = env_logger::try_init();
 
-		let client = Arc::new(polkadot_test_runtime_client::new());
+		let client = Arc::new(TestClientBuilder::new().build());
 
 		let mut push_blocks = {
 			let mut client = client.clone();
-			let mut base = 0;
 
 			move |n| {
-				for i in 0..n {
-					let mut builder = client.new_block(Default::default()).unwrap();
-
-					for extrinsic in polkadot_test_runtime_client::needed_extrinsics(base + i) {
-						builder.push(extrinsic).unwrap()
-					}
-
-					let block = builder.build().unwrap().block;
+				for _ in 0..n {
+					let block = client.init_polkadot_block_builder().build().unwrap().block;
 					client.import(BlockOrigin::Own, block).unwrap();
 				}
-
-				base += n;
 			}
 		};