资料内容：

Instrumented Tests with Espresso and

ActivityScenario

Let’s move on to instrumented tests. Begin by checking out the example

that Android Studio created. In

com.bignerdranch.android.geoquiz (androidTest), find

and open ExampleInstrumentedTest.kt:

@RunWith(AndroidJUnit4::class)

class ExampleInstrumentedTest {

@Test

fun useAppContext() {

// Context of the app under test.

val appContext = InstrumentationRegistry.getInstrumentation().targetContext

assertEquals("com.bignerdranch.android.geoquiz", appContext.packageName)

}

}

Much of this code is similar to the tests you have seen so far: You have a

class containing a function annotated with @Test, and within that function

there is an assertion to verify some behavior. But there are also some

differences: First, the class itself has an annotation,

@RunWith(AndroidJUnit4::class), which signals to JUnit that

this test should be executed on an Android device. And the test function

relies on the Android SDK, specifically to verify that the app’s package

name is the same as the value you set when you created the app.

You are about to run ExampleInstrumentedTest, but you have some

housekeeping to take care of first. Since instrumented tests run on an

Android device, not your development machine, you need to either connect

an Android device, as you did in Chapter 2, or run an emulator. Make sure

the device dropdown at the top of the Android Studio window shows the