Android 仪器测试：没有仪器注册错误

Question

I am trying to write Android Instrumented test using Espresso. When I run the test I get this error

java.lang.IllegalStateException: No instrumentation registered! Must run under a registering instrumentation.

I can't understand what this error means.

I will briefly explain what I am doing in my test. I followed the samples given by google and EspressoTesting Tutorial

@SmallTest
@RunWith(AndroidJUnit4.class)
public class ActivityInputTest {

   @Rule
   public ActivityTestRule<ActivityInput> aiRule = new ActivityTestRule<>(ActivityInput.class);


   @Before
   public void setUp(){}
}

When I run the test the error occurs at annotation @Rule . Can I get some explanation why this happens or what is the issue behind this? I am not interested in working code but more on the actual problem behind the issue.

Answer 1

I also experienced error exactly same with you, because I used androidx library. I suggest you to check your libraries in build.gradle and change your dependencies for UI test like these block codes:

androidTestImplementation "com.android.support.test:runner:1.0.2"
androidTestImplementation "com.android.support.test:rules:1.0.2"
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

Choose one of them, using com.android.support.test , or androidx library, because if we use them together, they will conflict each other. Hope this can help you to resolve error No instrumentation registered! Must run under a registering instrumentation. No instrumentation registered! Must run under a registering instrumentation.

Answer 2

Changing how I retrieved the context from:

@Before
public void setUp() {
    context = ApplicationProvider.getApplicationContext();
}

to the deprecated way :

@Before
public void setUp() {
    context = RuntimeEnvironment.application;
}

solved the issue for me.