Question

初始化JavaFX运行时的正确方法是什么，以便您可以使用并发工具和Platform.runLater(Runnable)进行单元测试（使用JUnit）控制器？

从Application.launch(...)方法调用@BeforeClass会导致死锁。如果未调用Application.launch(...)，则抛出以下错误：


java.lang.IllegalStateException: Toolkit not initialized
    at com.sun.javafx.application.PlatformImpl.runLater(PlatformImpl.java:121)
    at com.sun.javafx.application.PlatformImpl.runLater(PlatformImpl.java:116)
    at javafx.application.Platform.runLater(Platform.java:52)
    at javafx.concurrent.Task.runLater(Task.java:1042)
    at javafx.concurrent.Task.updateMessage(Task.java:987)
    at com.xyz.AudioSegmentExtractor.call(AudioSegmentExtractor.java:64)
    at com.xyz.CompletionControllerTest.setUp(CompletionControllerTest.java:69)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

跟进：这是我根据@SergeyGrinev推荐使用的主题。

... // Inside test class

public static class AsNonApp extends Application {
    @Override
    public void start(Stage primaryStage) throws Exception {
        // noop
    }
}

@BeforeClass
public static void initJFX() {
    Thread t = new Thread("JavaFX Init Thread") {
        public void run() {
            Application.launch(AsNonApp.class, new String[0]);
        }
    };
    t.setDaemon(true);
    t.start();
}
... // controller tests follow...

Answer 1

从launch()致电@BeforeClass是正确的方法。请注意，launch()不会将控制权返回给调用代码。所以你必须把它包装成new Thread(...).start()。

Answer 2

我发现这可以工作，但只是在启动JavaFX应用程序线程后添加Thread.sleep（500）之后。大概需要一些时间来准备FX环境（我的MacBook Pro视网膜上约200ms）

@BeforeClass
public static void setUpClass() throws InterruptedException {
    // Initialise Java FX

    System.out.printf("About to launch FX App\n");
    Thread t = new Thread("JavaFX Init Thread") {
        public void run() {
            Application.launch(AsNonApp.class, new String[0]);
        }
    };
    t.setDaemon(true);
    t.start();
    System.out.printf("FX App thread started\n");
    Thread.sleep(500);
}

Answer 3

这对我也适用于测试使用 JavaFX 并发构造（例如 javafx.concurrent.Task）的代码。与其他解决方案相比，它不需要显式线程管理或提供虚拟 Application。

@BeforeAll
public static void setUpJavaFXRuntime() throws InterruptedException {
    CountDownLatch latch = new CountDownLatch(1);
    Platform.startup(() -> {
        latch.countDown();
    });
    latch.await(5, TimeUnit.SECONDS);
}

@AfterAll
public static void tearDownJavaFXRuntime() throws InterruptedException {
    Platform.exit();
}

如何使用JUnit对JavaFX控制器进行单元测试

3 个答案: