我正在尝试通过扩展测试类来为我的应用程序中的活动编写单元测试用例ActivityUnitTestCase
。我可以更早地成功运行测试用例,但现在我在运行它们时总是遇到异常。尽管我对处理非常熟悉,但NullPointerExceptions
我无法弄清楚导致这种情况的问题。我找不到任何类似的问题,所以我发布了这个。
堆栈跟踪显示我的代码中的这一行有一个空对象引用
activity = startActivity(mIntent, null, null);
但是该startActivity
方法应该获取我正在测试的活动的实例。我不确定它为什么返回 null。
这是堆栈跟踪。
java.lang.NullPointerException: Attempt to write to field 'android.os.IBinder android.app.ActivityThread.mLastIntendedActivityToken' on a null object reference
at android.app.Activity.performCreate(Activity.java:6372)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
at android.support.test.runner.MonitoringInstrumentation.callActivityOnCreate(MonitoringInstrumentation.java:346)
at android.test.ActivityUnitTestCase.startActivity(ActivityUnitTestCase.java:158)
at com.abc.test.MainActivityTest.access$100(MainActivityTest.java:16)
at com.abc.test.MainActivityTest$1.run(MainActivityTest.java:34)
at android.app.Instrumentation$SyncRunnable.run(Instrumentation.java:1891)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6117)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
Test running failed: Instrumentation run failed due to 'java.lang.NullPointerException'
这是测试类
public class MainActivityTest extends ActivityUnitTestCase<MainActivity>{
private Intent mIntent;
private MainActivity activity;
public MainActivityTest() {
super(MainActivity.class);
}
@Override
protected void setUp() throws Exception {
super.setUp();
//Create an intent to launch target Activity as it is not automatically started by Android Instrumentation
mIntent = new Intent(getInstrumentation().getContext(), MainActivity.class);
//Start the activity under test in isolation, in the main thread to avoid assertion error.
getInstrumentation().runOnMainSync(new Runnable() {
@Override
public void run() {
activity = startActivity(mIntent, null, null);
}
});
}
@Override
protected void tearDown() throws Exception {
super.tearDown();
}
/**
* Tests the preconditions of this test fixture.
*/
@SmallTest
public void testPreconditions() {
assertNotNull("MainActivity is null", getActivity());
}
@MediumTest
public void testSecondActivityWasLaunchedWithIntent() {
// Get the intent for the next started activity
final Intent launchIntent = getStartedActivityIntent();
//Verify the intent was not null.
assertNotNull("Intent was null", launchIntent);
//Verify that LaunchActivity was finished
assertTrue(isFinishCalled());
}
}