testing-pyramid

To structure Android tests using the testing pyramid, you implement unit tests for ViewModels and UseCases, Hilt integration tests with an in-memory database, and Espresso tests for UI navigation smoke checks.

Writing Hilt integration tests with an in-memory database involves using Hilt testing rules to inject dependencies, replacing the actual database with an in-memory version, and verifying data flow through repository layers.

Mocking coroutines and ViewModels for Android unit tests using MockK involves applying reusable templates for setup, defining mock behaviors for suspend functions, and verifying interactions according to established project patterns.

You need MockK and JUnit alongside Android testing rules to run Espresso tests for navigation, as they provide the required mocking and assertion framework support to verify UI behavior and navigation smoke checks consistently.

The best way to reduce boilerplate when creating Espresso UI tests for Android is to apply reusable templates for setup, mocks, and verifications, ensuring consistent test naming conventions and structure across the app stack.

An Android testing strategy fails to validate data flow across repository layers when it lacks Hilt integration tests with an in-memory database, missing the necessary environment to verify interactions and data movement between layers.