zentol commented on a change in pull request #15251: URL: https://github.com/apache/flink/pull/15251#discussion_r597630826
########## File path: flink-runtime/src/test/java/org/apache/flink/runtime/scheduler/adaptive/BackgroundTaskTest.java ########## @@ -0,0 +1,148 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.flink.runtime.scheduler.adaptive; + +import org.apache.flink.core.testutils.FlinkMatchers; +import org.apache.flink.core.testutils.OneShotLatch; +import org.apache.flink.testutils.executor.TestExecutorResource; +import org.apache.flink.util.TestLogger; + +import org.hamcrest.Matchers; +import org.junit.ClassRule; +import org.junit.Test; + +import java.util.concurrent.ArrayBlockingQueue; +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Executors; + +import static org.junit.Assert.assertThat; +import static org.junit.Assert.assertTrue; +import static org.junit.Assert.fail; + +/** Tests for the {@link BackgroundTask}. */ +public class BackgroundTaskTest extends TestLogger { Review comment: I'm interested in the behavior for the case where we have `b1 -> b2`, and `b1` fails. I initially read the code such that `b2` would still run, but that is not the case because we use `thenApplyAsync`. This was a bit surprising actually; the javadocs for the BackGroundTask don't make this clear because they don't contain any notion of failed executions. Conceptually I considered this to just be queue that we pull from with some CompletableFuture sugar. I'm not sure if the behavior is really desired. Shouldn't background tasks that don't have anything to do with each other be independent? If a dependency is required then the result future should be used to make this explicit? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
