Espresso No views in hierarchy found matching: with id is id/btn

Question

Android

I have only one button on the screen with id btn, in the test I press it, and as I read, check(matches(isDisplayed()) means check the display of the screen, when the test starts, the button is pressed, the transition to another activity is performed (as and it should be), but in the test it writes an error Espresso No views in hierarchy found matching: with id is id/btn
I don’t understand what is the reason, because I have this button and it is pressed in the test
.

class MainActivityTest{
    @Rule
    fun activityTestRule():ActivityScenarioRule<MainActivity> = ActivityScenarioRule(MainActivity::class.java)
    @Test
    fun clickBTN(){
        onView(withId(R.id.btn)).perform(click()).check(matches(isDisplayed()))
    }
}

Answer 1

wrong sequence of writing code.