併發執行測試用例目的很簡單:就是爲了高效使用資源降低測試時間,俗話說天下武功,唯快不破,對,就是求追速度。
Junit中有關並行執行測試的關鍵組件爲ParallelComputer,ParallelComputer的基類爲Computer。Computer在Junit項目中是一個執行runners或者suites的角色(Runner是一個執行測試用例的執行器;Suite繼承至Runner,Suite允許將多個測試用例封裝到一個suite中)。所以爲了併發測試就需要使用ParallelComputer類,先簡單分析一下ParallelComputer的源碼簡單瞭解一下實現原理,對以後的使用應該幫助還是比較有好處的。ParallelComputer源碼如下:
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import org.junit.runner.Computer;
import org.junit.runner.Runner;
import org.junit.runners.ParentRunner;
import org.junit.runners.model.InitializationError;
import org.junit.runners.model.RunnerBuilder;
import org.junit.runners.model.RunnerScheduler;
public class ParallelComputer extends Computer {
private final boolean classes;
private final boolean methods;
//參數1:測試類是否併發執行, 參數2:測試方法是否併發執行
public ParallelComputer(boolean classes, boolean methods) {
this.classes = classes;
this.methods = methods;
}
public static Computer classes() {
return new ParallelComputer(true, false);
}
public static Computer methods() {
return new ParallelComputer(false, true);
}
// 實現併發執行的關鍵方法,在該方法中使用線程池實現併發測試
private static Runner parallelize(Runner runner) {
if (runner instanceof ParentRunner) {
// 重點代碼處:setScheduler方法是設置測試執行器(Runner)爲並行執行器,因此可以得以並行執行
((ParentRunner<?>) runner).setScheduler(new RunnerScheduler() {
//創建一個線程池,用於執行測試用例
private final ExecutorService fService = Executors.newCachedThreadPool();
//用於提交測試用例
public void schedule(Runnable childStatement) {
fService.submit(childStatement);
}
//所有測試用例執行完畢之後釋放資源
public void finished() {
try {
fService.shutdown();
fService.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
} catch (InterruptedException e) {
e.printStackTrace(System.err);
}
}
});
}
return runner;
}
@Override
public Runner getSuite(RunnerBuilder builder, java.lang.Class<?>[] classes)
throws InitializationError {
Runner suite = super.getSuite(builder, classes);
//通過classes字段是否並行執行測試用例類
return this.classes ? parallelize(suite) : suite;
}
@Override
protected Runner getRunner(RunnerBuilder builder, Class<?> testClass)
throws Throwable {
Runner runner = super.getRunner(builder, testClass);
//通過methods方法判斷是否並行執行測試方法
return methods ? parallelize(runner) : runner;
}
}
ParallelComputer的關鍵代碼說明見註釋。接下來看一下如何使用併發執行測試用例,測試用例如下:
import org.junit.Test;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.not;
/**
* Created by daxin on 2018/6/9.
*/
public class TestA {
@Test
public void testA() {
ConcurrentTest.printThreadName();
assertThat(3, is(1));
}
@Test
public void testB() {
ConcurrentTest.printThreadName();
assertThat(3, not(1));
}
}
import org.junit.Test;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.greaterThan;
import static org.hamcrest.Matchers.lessThan;
public class TestB {
@Test
public void testC() {
ConcurrentTest.printThreadName();
assertThat(3, greaterThan(1));
}
@Test
public void testD() {
ConcurrentTest.printThreadName();
assertThat(3, lessThan(1));
}
}
併發測試的示例代碼:
import org.junit.experimental.ParallelComputer;
import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
public class ConcurrentTest {
/**
* 該方法在真是測試環境下沒有實際用途,只是爲了驗證是否是併發測試
*/
public static void printThreadName() {
System.out.println("線程名字 = " + Thread.currentThread().getName());
}
public static void main(String[] args) {
Class[] cls = {TestA.class, TestB.class};
//JUnitCore是一個執行測試用例的門面(facade設計模式)
//ParallelComputer:兩個參數分別表示類和方法都並行執行
Result rt = JUnitCore.runClasses(new ParallelComputer(true, true), cls);
//打印執行結果
System.out.println(rt.getRunCount() + " " + rt.getRunTime());
System.out.println("================華麗的分割線==================");
rt.getFailures().forEach(System.out::println);
}
}
輸出結果信息如下:
通過打印線程名字客戶以看出JUint是以併發的方式執行測試用例。分割線下面可以看出各個存在問題的測試用例的信息。