Generate Unit Tests for Benchmarks (#5527)

* Update to latest staking

* generate tests for benchmarking

* add tests, fix warnings

* starting on democracy

* impl_benchmark_tests

* Way more readable

* add test feature flag (does this work?)

* Fix `successful_origin` impl

* democracry benchmark tests

* Fix example benchmarks, add tests

* identity benchmark tests

* Update im-online benchmark tests

* try to add session benchmarking tests (problem with mock)

* staking and timestamp

* add test for treasury, issue with dynamic contains

* utility

* Vesting

* test instead of check

* hide until we figure out what is wrong

* add docs

* close code

* Create custom mock for session-pallet-benchmarking

* Use refcell pattern

* make un-pub

* test-linux-stable includes `runtime-benchmarks` feature

* Revert "test-linux-stable includes `runtime-benchmarks` feature"

This reverts commit a2dab38abd18ac3eb8a6220e4a00e687740bd38c.

* run tests in `--release`

* undo balance change

* build wasm

substrate/frame/timestamp/src/benchmarking.rs

@@ -34,3 +34,17 @@ benchmarks! {
 		let n in ...;
 	}: _(RawOrigin::None, n.into())
 }
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::tests::{new_test_ext, Test};
+	use frame_support::assert_ok;
+
+	#[test]
+	fn test_benchmarks() {
+		new_test_ext().execute_with(|| {
+			assert_ok!(test_benchmark_set::<Test>());
+		});
+	}
+}