Challenge 2: A Compose UI Test — Solution

class CounterScreenTest {

    @get:Rule
    val composeTestRule = createComposeRule()

    @Test
    fun clickingIncrementTwiceShowsCountTwo() {
        composeTestRule.setContent {
            CounterScreen()
        }

        composeTestRule.onNodeWithText("Increment").performClick()
        composeTestRule.onNodeWithText("Increment").performClick()

        composeTestRule.onNodeWithText("Count: 2").assertIsDisplayed()
    }
}

Notes:
- @get:Rule is a use-site target (Kotlin Intermediate Chapter 6) —
  required here because JUnit's @Rule annotation must apply to the
  Kotlin property's underlying field/getter specifically for JUnit's
  test runner to recognize it correctly.
- composeTestRule.setContent { CounterScreen() } is the Compose-testing
  equivalent of what setContent { } does in a real MainActivity
  (Course 2, Chapter 1) — it renders the composable into a test
  environment without needing an actual running app.
- performClick() is called twice, each time re-locating the button via
  onNodeWithText("Increment") — since the button's own text doesn't
  change between clicks (only the Count text does), the same lookup
  works for both taps.
- assertIsDisplayed() confirms the node exists AND is visible on
  screen — a node existing in the composition tree but not actually
  shown would fail this specific assertion.