Merge branch 'cassandra-3.11' into cassandra-4.0

doc/source/development/testing.rst

@@ -65,6 +65,11 @@ Long running tests
 
 Test that consume a significant amount of time during execution can be found in the ``test/long`` directory and executed as a regular JUnit test or standalone program. Except for the execution time, there’s nothing really special about them. However, ant will execute tests under ``test/long`` only when using the ``ant long-test`` target.
 
+Flaky tests
+-----------
+
+If a test failure is difficult to reproduce you can always use a shell loop, circle repeat strategy and similar solutions. At the JUnit level ``RepeatableRunner`` will let you run a JUnit class N times for convenience. On tests that are fast this is a much faster way to iterate than doing it at the shell level. Beware of tests that modify singleton state or similar as they won't work.
+
 DTests
 ======
 

test/unit/org/apache/cassandra/CassandraIsolatedJunit4ClassRunner.java

@@ -26,8 +26,6 @@ import org.junit.runners.BlockJUnit4ClassRunner;
 import org.junit.runners.model.InitializationError;
 
 import org.apache.cassandra.distributed.impl.AbstractCluster;
-import org.apache.cassandra.distributed.shared.Versions;
-import org.apache.cassandra.utils.FBUtilities;
 
 /**
  *

test/unit/org/apache/cassandra/RepeatableRunner.java

@@ -0,0 +1,109 @@
+/*
+ * 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.cassandra;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.junit.internal.builders.AllDefaultPossibilitiesBuilder;
+import org.junit.runner.Description;
+import org.junit.runner.Runner;
+import org.junit.runner.notification.RunNotifier;
+import org.junit.runners.BlockJUnit4ClassRunner;
+import org.junit.runners.model.RunnerBuilder;
+
+/**
+ * This class comes useful when debugging flaky tests that will fail only when the full test suite is ran. It is
+ * intended for test failure investigation only.
+ * <p>
+ * Decorate your class with the runner and iterations you want. Defaults to 10.
+ * Beware of tests that change singleton status as those won't work.
+ * <pre>{@code
+ * @RunWith(RepeatableRunner.class)
+ * @RepeatableRunnerConfiguration(iterations = 2, runner = BlockJUnit4ClassRunner.class)
+ * public class MyTest
+ * {
+ * ...
+ * }
+ * }</pre>
+ */
+public class RepeatableRunner extends Runner
+{
+    private static final int DEFAULT_REPETITIONS = 10;
+    private static final Class<? extends Runner> DEFAULT_RUNNER_CLASS = BlockJUnit4ClassRunner.class;
+
+    private final Runner runner;
+    private final int iterations;
+
+    public RepeatableRunner(Class<?> testClass) throws Throwable
+    {
+        Class<? extends Runner> runnerClass = DEFAULT_RUNNER_CLASS;
+
+        if (testClass.isAnnotationPresent(RepeatableRunnerConfiguration.class))
+        {
+            RepeatableRunnerConfiguration configuration = testClass.getAnnotation(RepeatableRunnerConfiguration.class);
+            iterations = configuration.iterations();
+            runnerClass = configuration.runner();
+        }
+        else
+        {
+            iterations = DEFAULT_REPETITIONS;
+        }
+
+        runner = buildRunner(runnerClass, testClass);
+    }
+
+    @Override
+    public Description getDescription()
+    {
+        return runner.getDescription();
+    }
+
+    @Override
+    public void run(RunNotifier notifier)
+    {
+        for (int i = 0; i < iterations; i++)
+        {
+            runner.run(notifier);
+        }
+    }
+
+    private static Runner buildRunner(Class<? extends Runner> runnerClass, Class<?> testClass) throws Throwable
+    {
+        try
+        {
+            return runnerClass.getConstructor(Class.class).newInstance(testClass);
+        }
+        catch (NoSuchMethodException e)
+        {
+            return runnerClass.getConstructor(Class.class, RunnerBuilder.class)
+                              .newInstance(testClass, new AllDefaultPossibilitiesBuilder(true));
+        }
+    }
+
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target(ElementType.TYPE)
+    public @interface RepeatableRunnerConfiguration
+    {
+        int iterations() default DEFAULT_REPETITIONS;
+
+        Class<? extends Runner> runner() default BlockJUnit4ClassRunner.class;
+    }
+}