java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.test.espresso.intent.Intents.internalIntended(org.hamcrest.Matcher,android.support.test.espresso.intent.VerificationMode,java.util.List)' on a null object reference

这是我的Test类：

import android.support.test.rule.ActivityTestRule;
import android.support.test.runner.AndroidJUnit4;

import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;

import static android.support.test.espresso.Espresso.onView;
import static android.support.test.espresso.action.ViewActions.click;
import static android.support.test.espresso.action.ViewActions.typeText;
import static android.support.test.espresso.intent.Intents.intended;
import static android.support.test.espresso.intent.matcher.IntentMatchers.hasComponent;
import static android.support.test.espresso.matcher.ViewMatchers.withId;

@RunWith(AndroidJUnit4.class)
public class LoginActivityTest {

    @Rule
    public ActivityTestRule<LoginActivity> mLoginActivityActivityTestRule =
            new ActivityTestRule<>(LoginActivity.class);

    @Test
    public void clickLoginButton_ShowsSnackBarRightCredentials() throws Exception {

        onView(withId(R.id.login_email)).perform(typeText("a@aa.aa"));
        onView(withId(R.id.login_password)).perform(typeText("11111111"));
        onView(withId(R.id.email_sign_in_button)).perform(click());

        intended(hasComponent(MainActivity.class.getName()));

    }
}

我在之前的问题中发现这行代码应该对我有帮助,但是这一行产生了NullPointer.

意图(hasComponent(MainActivity.classenter code here.getName()));

我怎样才能解决这个问题？我究竟做错了什么？

这是完整的堆栈跟踪：

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.test.espresso.intent.Intents.internalIntended(org.hamcrest.Matcher,java.util.List)' on a null object reference
at android.support.test.espresso.intent.Intents$2.check(Intents.java:190)
at android.support.test.espresso.ViewInteraction$2.run(ViewInteraction.java:170)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:428)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)