我的课程看起来就像谷歌提供的那样：

import android.support.test.InstrumentationRegistry;
import android.support.test.runner.AndroidJUnit4;
import android.test.ActivityInstrumentationTestCase2;
import android.test.suitebuilder.annotation.LargeTest;
 
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
 
import static android.support.test.espresso.matcher.ViewMatchers.assertThat;
import static org.hamcrest.Matchers.notNullValue;
 
@RunWith(AndroidJUnit4.class)
@LargeTest
public class MyCoolActivityTests extends ActivityInstrumentationTestCase2<MyCoolActivity> {
 
    private MyCoolActivity mActivity;
 
    public MyCoolActivityTests() {
        super(MyCoolActivity.class);
    }
 
    @Before
    public void setUp() throws Exception {
        super.setUp();
        injectInstrumentation(InstrumentationRegistry.getInstrumentation());
        mActivity = getActivity();
    }
 
    @Test
    public void checkPreconditions() {
        assertThat(mActivity,notNullValue());
        // Check that Instrumentation was correctly injected in setUp()
        assertThat(getInstrumentation(),notNullValue());
    }
 
    @After
    public void tearDown() throws Exception {
        super.tearDown();
    }
}

我已经为build.gradle添加了所​​有必要的东西：

android {
    defaultConfig {
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
}
 
dependencies {
    androidTestCompile 'com.android.support.test.espresso:espresso-core:2.0'
    androidTestCompile 'com.android.support.test:testing-support-lib:0.1'
}

有没有办法让这个警告消失？