Instrumented tests in Android Kotlin - Build, Publish & Deploy

Build & Publish - Instrumented tests

Performance Impact of Instrumented Tests

Instrumented tests run on real or virtual Android devices. They do not affect your app's runtime performance for users because they run separately from the app's production code.

However, running many or complex instrumented tests can consume significant CPU and memory on the test device or emulator, which may slow down test execution and drain battery faster during testing.

Instrumented tests do not impact your app's frame rate or memory usage in production.

💻

Optimizing Instrumented Tests for Faster Execution

• Keep tests focused and small to reduce execution time.
• Use AndroidJUnitRunner efficiently and avoid unnecessary setup or teardown steps.
• Run tests on fast emulators or physical devices with good performance.
• Use adb shell am instrument commands with filters to run only relevant tests.
• Mock external dependencies to avoid slow network or database operations.
• Parallelize tests when possible using Gradle test options.

Impact on App Bundle Size and Startup Time

Instrumented tests are packaged separately from your app's release APK or AAB. They do not increase your app's bundle size or affect startup time for end users.

Test APKs include test code and dependencies, which increase the size of the test package but this is only relevant during development and CI pipelines.

iOS vs Android Differences for Instrumented Tests

Android instrumented tests run on devices or emulators using AndroidJUnitRunner and access app context.

iOS uses XCTest framework for UI and integration tests, running on simulators or devices with Xcode tools.

Android tests require androidTest source sets and Gradle configuration, while iOS tests are integrated into Xcode projects.

Both platforms separate test code from production code to avoid impacting app performance.

Store Review Guidelines and Requirements

• Instrumented tests are for development only and are not included in app store submissions.
• Ensure no test code or debug flags remain in your release APK or AAB to comply with Google Play policies.
• Remove or disable any test-only permissions or features before publishing.
• Follow Google Play's security and privacy guidelines to avoid exposing test endpoints or data.

Self-Check: Your App Takes 5 Seconds to Load This Screen. What's Likely Wrong?

If your instrumented test runs slowly or your app screen loads slowly during testing, possible issues include:

• Tests performing heavy UI operations or waiting unnecessarily.
• Network calls or database queries not mocked, causing delays.
• Running tests on slow emulators or overloaded devices.
• Excessive setup or teardown steps in tests.

Optimizing test code and environment can improve speed and reliability.

Key Result

Instrumented tests run separately from your app and do not affect user performance or app size. Optimize tests for speed by keeping them small, mocking dependencies, and running on fast devices. Ensure no test code is included in release builds to meet store guidelines.