Compose UI testing in Android Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ ui_behavior

intermediate

What is the output of this Compose UI test code?

Given the Compose UI test code below, what will the test verify successfully?

Android Kotlin

composeTestRule.setContent {
  Button(onClick = {}) {
    Text("Click Me")
  }
}
composeTestRule.onNodeWithText("Click Me").assertIsDisplayed()

A The test fails because the text 'Click Me' is not found in the UI.

B The test fails because the button has no click action defined.

C The test passes because the button with text 'Click Me' is displayed.

D The test passes but does not check if the button is clickable.

💡 Hint

Look for the text inside the Button and what the test is asserting.

The test sets a Button with text 'Click Me' and asserts that a node with this text is displayed. Since the text exists, the test passes.

❓ lifecycle

intermediate

What happens if you call composeTestRule.setContent twice in a test?

In a Compose UI test, what is the effect of calling setContent twice with different Composables?

A The second setContent replaces the first UI content completely.

B Both Composables are shown simultaneously on the screen.

C The test will crash due to multiple setContent calls.

D The first Composable remains visible and the second is ignored.

💡 Hint

Think about how Compose manages UI content in tests.

Calling setContent again replaces the previous UI content with the new Composable, so only the second UI is visible.

🔧 Debug

advanced

Why does this Compose test fail with NoMatchingNodeException?

This test fails with NoMatchingNodeException: composeTestRule.setContent { Text("Hello World") } composeTestRule.onNodeWithText("Hello").assertIsDisplayed()

A The test fails because assertIsDisplayed is not a valid assertion.

B The test fails because the Text composable is not clickable.

C The test fails because setContent was not called on the main thread.

D The text 'Hello' does not exactly match 'Hello World', so no node is found.

💡 Hint

Check the exact text string used in the test and in the UI.

The test looks for a node with exact text 'Hello', but the UI shows 'Hello World'. This mismatch causes NoMatchingNodeException.

❓ navigation

advanced

How to test navigation between two Compose screens?

You have two Composables: ScreenA and ScreenB. ScreenA has a button that navigates to ScreenB. Which test code correctly verifies navigation?

Android Kotlin

composeTestRule.setContent {
  NavHost(navController, startDestination = "screenA") {
    composable("screenA") { ScreenA(navController) }
    composable("screenB") { ScreenB() }
  }
}
composeTestRule.onNodeWithText("Go to B").performClick()
// What assertion verifies navigation?

A composeTestRule.onNodeWithText("Screen B Content").assertIsDisplayed()

B composeTestRule.onNodeWithText("Go to B").assertIsDisplayed()

C composeTestRule.onNodeWithTag("screenA").assertIsDisplayed()

D composeTestRule.onNodeWithText("Screen A Content").assertIsDisplayed()

💡 Hint

After clicking the button, the UI should show ScreenB content.

After performing click on the navigation button, the test should verify that ScreenB's content is displayed to confirm navigation.

🧠 Conceptual

expert

What is the role of Semantics in Compose UI testing?

Why is setting semantics properties important for Compose UI testing?

A They improve the app's performance by reducing recompositions.

B They provide metadata that test code uses to find and interact with UI elements.

C They automatically generate UI screenshots for tests.

D They prevent UI elements from being displayed on the screen.

💡 Hint

Think about how tests identify UI elements beyond visible text.

Semantics add descriptive information to UI elements, enabling tests to locate and interact with them reliably, especially when text is not unique or present.