com.cueup.hegemon.TestUtils.java Source code

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Here is the source code for com.cueup.hegemon.TestUtils.java

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/*
 * Copyright 2012 the hegemon authors.
 *
 * 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.cueup.hegemon;

import com.google.common.base.Joiner;
import com.google.common.collect.Lists;
import org.apache.commons.lang.exception.ExceptionUtils;
import org.junit.Assert;

import java.util.List;

/**
 * Utilities for tests.
 */
public class TestUtils {

    private TestUtils() {
    }

    /**
     * Utility class that collects errors from sub-threads.
     */
    private static class ErrorCollector implements Thread.UncaughtExceptionHandler {

        private final List<String> errors = Lists.newArrayList();

        @Override
        public synchronized void uncaughtException(Thread thread, Throwable throwable) {
            this.errors.add(thread.getName() + ": " + ExceptionUtils.getFullStackTrace(throwable));
        }

        public void assertNoErrors() {
            if (!this.errors.isEmpty()) {
                Assert.fail(Joiner.on("\n\n").join(this.errors));
            }
        }

    }

    public static void runConcurrent(int count, Runnable r) throws InterruptedException {
        List<Thread> threads = Lists.newArrayList();
        ErrorCollector errorCollector = new ErrorCollector();

        for (int i = 0; i < count; i++) {
            Thread t = new Thread(r);
            t.setName("testThread" + i);
            t.setUncaughtExceptionHandler(errorCollector);
            threads.add(t);

        }

        for (Thread t : threads) {
            t.start();
        }

        for (Thread t : threads) {
            t.join();
        }

        errorCollector.assertNoErrors();
    }

}