| // Copyright 2021 The Bazel Authors. All rights reserved. |
| // |
| // Licensed 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 com.google.devtools.build.lib.remote.util; |
| |
| import io.reactivex.rxjava3.exceptions.CompositeException; |
| import io.reactivex.rxjava3.plugins.RxJavaPlugins; |
| import java.util.List; |
| import java.util.concurrent.CopyOnWriteArrayList; |
| import org.junit.rules.ExternalResource; |
| |
| /** |
| * A JUnit {@link org.junit.Rule} that captures uncaught errors from RxJava streams and rethrows |
| * them post-test if left unaddressed. |
| * |
| * <p>This is to prevent false-positives caused by RxJava's default uncaught error handler, which |
| * manually forwards the event to the current Thread's exception handler and bypasses JUnit's |
| * failure reporting. |
| * |
| * <p>Can also be used to assert that no uncaught errors have yet been thrown mid-test. This is |
| * useful to ensure tests are in a consistent state before continuing. |
| */ |
| public class RxNoGlobalErrorsRule extends ExternalResource { |
| private final List<Throwable> errors = new CopyOnWriteArrayList<>(); |
| |
| @Override |
| protected void before() { |
| RxJavaPlugins.setErrorHandler(errors::add); |
| } |
| |
| @Override |
| protected void after() { |
| assertNoErrors(); |
| } |
| |
| private static final class UncaughtRxErrors extends RuntimeException { |
| private UncaughtRxErrors(Throwable cause) { |
| super("There were uncaught Rx errors during test execution", cause); |
| } |
| } |
| |
| /** |
| * Asserts that no uncaught errors have yet occurred. |
| * |
| * <p>If an Rx stream has thrown an uncaught error any time before this method is called, an |
| * {@link UncaughtRxErrors} is thrown. This is useful for ensuring that tests are in a consistent |
| * state before continuing. |
| * |
| * <p>You may need to advance any test schedulers so that any pending events are flushed. |
| */ |
| private void assertNoErrors() { |
| if (errors.size() > 1) { |
| Throwable[] errorsArray = errors.toArray(new Throwable[0]); |
| throw new UncaughtRxErrors(new CompositeException(errorsArray)); |
| } else if (errors.size() == 1) { |
| throw new UncaughtRxErrors(errors.get(0)); |
| } |
| } |
| } |