Add a couple of tests to de-befuddle myself

Author: mrcnski

polkadot/node/core/pvf/tests/it/adder.rs

@@ -100,7 +100,7 @@ async fn execute_bad_block_on_parent() {
 
 	let host = TestHost::new();
 
-	let _ret = host
+	let _err = host
 		.validate_candidate(
 			adder::wasm_binary_unwrap(),
 			ValidationParams {
@@ -145,3 +145,37 @@ async fn stress_spawn() {
 
 	futures::future::join_all((0..100).map(|_| execute(host.clone()))).await;
 }
+
+// With one worker, run multiple execution jobs serially. They should not conflict.
+#[tokio::test]
+async fn execute_can_run_serially() {
+	let host = std::sync::Arc::new(TestHost::new_with_config(|cfg| {
+		cfg.execute_workers_max_num = 1;
+	}));
+
+	async fn execute(host: std::sync::Arc<TestHost>) {
+		let parent_head = HeadData { number: 0, parent_hash: [0; 32], post_state: hash_state(0) };
+		let block_data = BlockData { state: 0, add: 512 };
+		let ret = host
+			.validate_candidate(
+				adder::wasm_binary_unwrap(),
+				ValidationParams {
+					parent_head: GenericHeadData(parent_head.encode()),
+					block_data: GenericBlockData(block_data.encode()),
+					relay_parent_number: 1,
+					relay_parent_storage_root: Default::default(),
+				},
+				Default::default(),
+			)
+			.await
+			.unwrap();
+
+		let new_head = HeadData::decode(&mut &ret.head_data.0[..]).unwrap();
+
+		assert_eq!(new_head.number, 1);
+		assert_eq!(new_head.parent_hash, parent_head.hash());
+		assert_eq!(new_head.post_state, hash_state(512));
+	}
+
+	futures::future::join_all((0..5).map(|_| execute(host.clone()))).await;
+}

polkadot/node/core/pvf/tests/it/main.rs

@@ -18,8 +18,8 @@
 use assert_matches::assert_matches;
 use parity_scale_codec::Encode as _;
 use polkadot_node_core_pvf::{
-	start, Config, InvalidCandidate, Metrics, PrepareJobKind, PvfPrepData, ValidationError,
-	ValidationHost, JOB_TIMEOUT_WALL_CLOCK_FACTOR,
+	start, Config, InvalidCandidate, Metrics, PrepareError, PrepareJobKind, PrepareStats,
+	PvfPrepData, ValidationError, ValidationHost, JOB_TIMEOUT_WALL_CLOCK_FACTOR,
 };
 use polkadot_parachain_primitives::primitives::{BlockData, ValidationParams, ValidationResult};
 use polkadot_primitives::ExecutorParams;
@@ -70,6 +70,33 @@ impl TestHost {
 		Self { cache_dir, host: Mutex::new(host) }
 	}
 
+	async fn precheck_pvf(
+		&self,
+		code: &[u8],
+		executor_params: ExecutorParams,
+	) -> Result<PrepareStats, PrepareError> {
+		let (result_tx, result_rx) = futures::channel::oneshot::channel();
+
+		let code = sp_maybe_compressed_blob::decompress(code, 16 * 1024 * 1024)
+			.expect("Compression works");
+
+		self.host
+			.lock()
+			.await
+			.precheck_pvf(
+				PvfPrepData::from_code(
+					code.into(),
+					executor_params,
+					TEST_PREPARATION_TIMEOUT,
+					PrepareJobKind::Prechecking,
+				),
+				result_tx,
+			)
+			.await
+			.unwrap();
+		result_rx.await.unwrap()
+	}
+
 	async fn validate_candidate(
 		&self,
 		code: &[u8],
@@ -321,3 +348,19 @@ async fn deleting_prepared_artifact_does_not_dispute() {
 		r => panic!("{:?}", r),
 	}
 }
+
+// With one worker, run multiple preparation jobs serially. They should not conflict.
+#[tokio::test]
+async fn prepare_can_run_serially() {
+	let host = TestHost::new_with_config(|cfg| {
+		cfg.prepare_workers_hard_max_num = 1;
+	});
+
+	let _stats = host
+		.precheck_pvf(::adder::wasm_binary_unwrap(), Default::default())
+		.await
+		.unwrap();
+
+	// Prepare a different wasm blob to prevent skipping work.
+	let _stats = host.precheck_pvf(halt::wasm_binary_unwrap(), Default::default()).await.unwrap();
+}