Android Programming: The Big Nerd Ranch Guide, 5th Edition

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 ...