ChangeTextBehaviorTest.kt

@RunWith(AndroidJUnit4::class)
class ChangeTextBehaviorTest {

    @get:Rule
    var activityRule: ActivityTestRule<MainActivity> = ActivityTestRule(MainActivity::class.java)

    @Test
    fun changeText_sameActivity() {
        onView(withId(R.id.editTextUserInput)).perform(typeText("Espresso"), closeSoftKeyboard())

        onView(withId(R.id.changeTextBt)).perform(click())

        onView(withId(R.id.textToBeChanged)).check(matches(withText("Espresso")))
    }
}