Runtime benchmarks: start (#136)

* runtime benchmarks: start

* merge tests + benchmarks infrastructure

* fix compilation

* Fix compilation issues with runtime-benchmark feature flag

Mainly involved pulling in correct dependencies and adding some functions
which were called but didn't yet exist.

* Fix broken compilation for tests

* Move header signing methods into trait

* Move signing related test helpers to own module

* Remove comment about feature flag

* Add constants to tests

* Add top level comment for testing utilities

Co-authored-by: Hernando Castano <castano.ha@gmail.com>

bridges/bin/node/runtime/src/lib.rs

@@ -573,6 +573,27 @@ impl_runtime_apis! {
 			None
 		}
 	}
+
+	#[cfg(feature = "runtime-benchmarks")]
+	impl frame_benchmarking::Benchmark<Block> for Runtime {
+		fn dispatch_benchmark(
+			pallet: Vec<u8>,
+			benchmark: Vec<u8>,
+			lowest_range_values: Vec<u32>,
+			highest_range_values: Vec<u32>,
+			steps: Vec<u32>,
+			repeat: u32,
+		) -> Result<Vec<frame_benchmarking::BenchmarkBatch>, sp_runtime::RuntimeString> {
+			use frame_benchmarking::{Benchmarking, BenchmarkBatch, add_benchmark};
+			let mut batches = Vec::<BenchmarkBatch>::new();
+			let params = (&pallet, &benchmark, &lowest_range_values, &highest_range_values, &steps, repeat);
+
+			add_benchmark!(params, batches, b"bridge-eth-poa", BridgeEthPoA);
+
+			if batches.is_empty() { return Err("Benchmark not found for this pallet.".into()) }
+			Ok(batches)
+		}
+	}
 }
 
 #[cfg(test)]