applying-testing-strategies

To eliminate flaky Android instrumented tests, you must remove sources of non-determinism like coroutine delays, animation timing, randomness, and external state. This involves applying a determinism checklist for hermetic test execution.

Hilt UI testing dependency replacement requires using @HiltAndroidTest, HiltAndroidRule, and module replacement APIs like @TestInstallIn, @UninstallModules, and @BindValue. You must also enforce deterministic rule ordering and call inject().

Structuring Android test suites with Given-When-Then involves establishing a consistent Arrange-Act-Assert flow and a readable test method naming convention. This structure scales reliably and enables faster debugging.

You need @TestInstallIn and @UninstallModules for Hilt testing when replacing production modules in instrumented tests. Both APIs allow swapping dependencies, but @TestInstallIn provides the replacement module while @UninstallModules simply removes the original.

Android tests pass locally but fail in CI due to non-determinism from time dependencies, concurrency, animation timing, or external state. Structuring tests hermetically with dependency replacement eliminates these CI-only failures.

You can use HiltAndroidRule with other JUnit rules for Android integration testing, but you must enforce deterministic rule ordering. Correct rule ordering ensures Hilt dependency injection occurs reliably before test execution.