为了详细描述这些问题,我提供了我的测试类’简化伪代码和下面的三个问题.两个测试用例都是相互独立的.

public class FirstActivityTest 
extends ActivityInstrumentationTestCase2<FirstActivity> {
    private FirstActivity mActivity;
    private ActivityMonitor mActivityMonitor;

    public FirstActivityTest () {
        super(FirstActivity.class);
    }

    public void setUp() throws Exception {
        super.setUp();
        setActivityInitialTouchMode(false);

        mActivity = getActivity();
        assertNotNull("Cannot start test since target Activity is NULL!",mActivity);

        mActivityMonitor = getInstrumentation().addMonitor(SecondActivity.class.getName(),null,false);
    }

    public void tearDown() throws Exception {
        super.tearDown();
        if(mActivity != null) {
            mActivity.finish();
            mActivity = null;
        }
        if(mActivityMonitor != null) {
            getInstrumentation().removeMonitor(mActivityMonitor);
            mActivityMonitor = null;
        }
    }

    /**
     * Open FirstActivity,enter a text and click submit button. 
     * Verifies SecondActivity is open.
     */
    public void testA_HappyPath() {
        Activity secondActivity = null;
        try {
            //(Omitted) Get edit text and enter a valid value
            //(Omitted) Find submitButton view
            //Click submit button
            TouchUtils.clickView(this,submitButton);

            //Wait for result and validate:
            secondActivity = mActivityMonitor.waitForActivityWithTimeout(10000);
            assertNotNull("Result SecondActivity should NOT be null!",secondActivity );
        } finally {
            //Clean up:
            if(secondActivity != null) {
                secondActivity .finish();
                secondActivity = null;
            }
        }
    }

    /**
     * Open FirstActivity,do NOT enter a text and click submit button. 
     * Verifies error message is returned.
     */
    public void testB_Sadpath() {
        //(Omitted) Find submitButton view
        //Click submit button
        TouchUtils.clickView(this,submitButton);

        //(Omitted) Validate error message is displayed
    }
}

现在,我一遍又一遍地运行这两个测试用例(它们将按字母顺序运行),结果如下：

>两个测试用例都通过了,OR
> testA_HappyPath()失败,因为ActivityMonitor.waitForActivityWithTimeout()返回NULL SecondActivity.但是当我查看我的设备时,SecondActivity正确显示.不知何故,测试未能注意到它.为什么？
>当testA_HappyPath()失败时,下一个testB_Sadpath()将在setUp()>期间挂起. getActivity()无限期.我想我关闭了tearDown()中的所有内容.为什么？
> testB_Sadpath()经常在TouchUtils.clickView()上失败,并出现以下错误：“注入另一个应用程序需要INJECT_EVENTS权限”(无论testA_HappyPath通过还是失败).为什么？

任何有用的反馈表示赞赏.谢谢！

到目前为止,我已经处理了这三个问题,在互联网上研究了很多建议并做了几次尝试和错误.然而,没有一个人能够立即解决特定的问题 – 通过结合我发现的解决了上述问题(1)和(2)的问题,但仍然有问题(3)未解决.下面详细介绍了我为完成这项工作所做的修复.

ISSUE(1)ActivityMonitor.waitForActivityWithTimeout()返回NULL

1.1.我现在知道我必须在getActivit()之前声明getInstrumentation().addMonitor().请看我如何更改setUp()方法,这以某种方式修复了问题.任何了解这为何要求的人请告诉我们,我们对此表示赞赏.

1.2.在模拟器上,此调用偶尔会返回NULL,导致测试失败.我了解到这是因为等待时间太短了.因此,增加等待时间有助于防止ActivityMonitor过早返回.

问题(2)下一个testB_Sadpath()会在setUp()>期间挂起getActivity()无限期

2.1.如上所述,这发生在前一个测试(testA_HappyPath)失败时.我以为我的tearDown()清理了所有东西并准备好下一个测试.发生的事情是,testA正在等待SecondActivity出现在屏幕上,但由于ActivityMonitor.waitForActivityWithTimeout()返回NULL,testA失败. tearDown()执行得很好.问题是SecondActivity确实出现在屏幕上,但它永远不会在finally块中关闭,因为它的方法实例’secondActivity’仍为null.让SecondActivity活着并且在屏幕上徘徊导致下一个getActivity()挂起.我通过更改finally块来修复此问题,以确保SecondActivity是否存在,它会被关闭.

这些更改总结在下面的代码中(请参阅setUp()和finally块).

public class FirstActivityTest 
extends ActivityInstrumentationTestCase2<FirstActivity> {
    private FirstActivity mActivity;
    private ActivityMonitor mActivityMonitor;

    public FirstActivityTest () {
        super(FirstActivity.class);
    }

    public void setUp() throws Exception {
        super.setUp();
        setActivityInitialTouchMode(false);
    }

    public void tearDown() throws Exception {
        super.tearDown();
        if(mActivity != null) {
            mActivity.finish();
            mActivity = null;
        }
        if(mActivityMonitor != null) {
            getInstrumentation().removeMonitor(mActivityMonitor);
            mActivityMonitor = null;
        }
    }

    /**
     * Open FirstActivity,enter a text and click submit button. 
     * Verifies SecondActivity is open.
     */
    public void testA_HappyPath() {
        mActivityMonitor = getInstrumentation().addMonitor(SecondActivity.class.getName(),false);

        mActivity = getActivity();
        assertNotNull("Cannot start test since target Activity is NULL!",mActivity);

        Activity secondActivity = null;
        try {
            //(Omitted) Get edit text and enter a valid value
            //(Omitted) Find submitButton view
            //Click submit button
            TouchUtils.clickView(this,submitButton);

            //Wait for result and validate:
            secondActivity = mActivityMonitor.waitForActivityWithTimeout(20000);
            assertNotNull("Result SecondActivity should NOT be null!",secondActivity );
        } finally {
            //Clean up:
            if(secondActivity == null) {
                //If empty,wait longer because need to shut down the foreground activity,if any: 
                secondActivity = mActivityMonitor.waitForActivityWithTimeout(20000);
            }
            if(secondActivity != null) {
                secondActivity .finish();
                secondActivity = null;
            }
        }
    }

    /**
     * Open FirstActivity,do NOT enter a text and click submit button. 
     * Verifies error message is returned.
     */
    public void testB_Sadpath() {
        mActivity = getActivity();
        assertNotNull("Cannot start test since target Activity is NULL!",mActivity);

        //(Omitted) Find submitButton view
        //Click submit button
        TouchUtils.clickView(this,submitButton);

        //(Omitted) Validate error message is displayed
    }
}

ISSUE(3)testB_Sadpath()经常在TouchUtils.clickView()上失败,并出现以下错误：“注入另一个应用程序需要INJECT_EVENTS权限”

我还是无法解决最后一期:-(

我在Android单元测试中找到了另一种避免此问题的方法.我没有使用TouchUtils.clickView(),而是通过调用performClick()直接对按钮本身执行单击操作.以下修改过的测试代码解决了我偶尔的INJECT_EVENTS权限错误.特别是,请参阅populateDataAndClickSubmit().

/**
 * Open FirstActivity,enter a text and click submit button. 
 * Verifies SecondActivity is open.
 */
public void testA_HappyPath() {
    mActivityMonitor = getInstrumentation().addMonitor(SecondActivity.class.getName(),false);

    mActivity = getActivity();
    assertNotNull("Cannot start test since target Activity is NULL!",mActivity);

    Activity secondActivity = null;
    try {
        String dataValue = "MyNameIsNoLongerFoonorBar";
        populateDataAndClickSubmit(dataValue);

        //Wait for result and validate:
        secondActivity = mActivityMonitor.waitForActivityWithTimeout(20000);
        assertNotNull("Result SecondActivity should NOT be null!",secondActivity );
    } finally {
        //Clean up:
        if(secondActivity == null) {
            //If empty,if any: 
            secondActivity = mActivityMonitor.waitForActivityWithTimeout(20000);
        }
        if(secondActivity != null) {
            secondActivity.finish();
            secondActivity = null;
        }
    }
}

/**
 * Open FirstActivity,do NOT enter a text and click submit button. 
 * Verifies error message is returned.
 */
public void testB_Sadpath() {
    mActivity = getActivity();
    assertNotNull("Cannot start test since target Activity is NULL!",mActivity);

    String dataValue = null;
    populateDataAndClickSubmit(dataValue);

    //(Omitted) Validate error message is displayed
}

private void populateDataAndClickSubmit(final String dataValueString) {
    final EditText editDataView = //(omitted) find it from the activity layout
    final Button submitButton = //(Omitted) Find submitButton view

    mActivity.runOnUiThread(
            new Runnable() {
                public void run() {
                    editDataView.setText(dataValueString);
                    submitButton.performClick();
               }
            }
        );

    //Wait and allow app to be idle while performClick to finish and activity re-drawn:
    getInstrumentation().waitForIdleSync();
}

笔记：

>此解决方案不能解释为什么touchUtils.clickView()会引发偶尔的注入事件权限错误> View.performClick()要求您的活动让View中的View实现OnClickListener().就我而言,SubmitButton已经有了,所以它是一个方便测试代码更改.> getInstrumentation().waitForIdleSync()允许测试代码空闲,直到应用程序完成工作并适当地重新绘制其布局.如果查看其java代码,则在touchUtils.clickView()中执行相同的行.

例如：

int maxDurationMs = 1000;
        while (true)
        {
            DateTime dt = DateTime.UtcNow;
            DoQuickStuff()
            TimeSpan duration1 =  DateTime.UtcNow - dt;
            int sleepTime = maxDurationMs - duration1.Milliseconds;
            if (sleepTime > 0)
                System.Threading.Thread.Sleep(sleepTime);
        }

要么

// cpu Intensive,but fairly accurate
       int maxDurationMs = 1000;
        while (true)
        {
            DateTime dt = DateTime.UtcNow;
            DoQuickStuff()
            while (true)
            {
                if (dt.AddMilliseconds(maxDurationMs) >= DateTime.UtcNow)
                    break;
            }
        }

做同样事情的替代方法,但具有不同程度的准确性和权衡(cpu等)

> System.Timer
> DispatchTimer
> System.Threading.Timer
> Thread.Join
> .NET 4.0 Task
> Thread.Sleep()
> Monitor.Wait(obj,timespan)
> Multimedia Timers(感谢Brian Gideon)
> Win32 High Resolution timers
>还有别的吗？

另一种选择可能是在紧密循环中使用秒表和一些标准的Thread.Sleep调用.我不确定这种方法会带来多少运气,但它可能比普通的Thread.Sleep调用更准确.我从未尝试过,但我认为任何事都值得一试.

我做了一些实验,我发现将线程优先级更改为ThreadPriority.Highest有很大的不同.它在我尝试的每种技术上都相当减少了间隔的标准偏差.

@GwtIncompatible // threads

  public void testOverflowTimeout() throws Exception {
    // First,sanity check that naive multiplication would really overflow to a negative number:
    long nanosPerSecond = NANOSECONDS.convert(1,SECONDS);
    assertthat(nanosPerSecond * Long.MAX_VALUE).isLessthan(0L);

    // Check that we wait long enough anyway (presumably as long as MAX_VALUE nanos):
    TimedWaiterThread waiter = new TimedWaiterThread(future,Long.MAX_VALUE,SECONDS);
    waiter.start();
    waiter.awaitWaiting();

    future.set(1);
    waiter.join();
  }

@GwtIncompatible // threads

  public void testOverflowTimeout() throws Exception {
    // First,SECONDS);
    waiter.start();
    waiter.awaitWaiting();

    future.set(1);
    waiter.join();
  }

@GwtIncompatible // threads

  public void testOverflowTimeout() throws Exception {
    // First,SECONDS);
    waiter.start();
    waiter.awaitWaiting();

    future.set(1);
    waiter.join();
  }