By name: kmp-testing-quality description: Design and review KMP testing strategy, commonTest, kotlin.test, platform tests, Compose Multiplatform UI tests, screenshot tests, test doubles, refactor safety, code review gates, and regression validation.
KMP Testing And Quality
Use for KMP test strategy/review: commonTest, kotlin.test, platform tests, Compose Multiplatform UI tests, screenshot tests, test doubles, refactor safety, code review gates, regression validation.
Strategy
Favor confidence/speed over coverage vanity:
- Many shared/unit tests.
- Fewer integration tests.
- Fewer UI/end-to-end than lower-level tests.
- Behavior-focused assertions.
- Deterministic test data/fake dependencies.
Placement
- Put shared business logic in
commonTestfirst. - Shared tests should use
kotlin.test, not JUnit-only APIs. - Android framework behavior belongs in Android-only local/instrumented tests.
- Robolectric is Android-only; never in
commonTest. - Non-shared iOS/native behavior should be validated via native target tasks/Xcode.
- Compose shared UI tests should focus on semantics/observable behavior.
- Compose Multiplatform UI tests should use current Compose testing API and target-specific setup.
- Verify source-set/dependency instructions against current docs before editing Gradle files.
Test First
- Business rules.
- DTO/domain/UI mapping.
- Repository coordination logic.
- State-holder transitions.
- Error/retry/cancellation/stale-data behavior.
- Navigation decisions/one-shot effects when important.
- Migration/refactor regressions.
- Security-sensitive flows: token refresh, logout, stale credentials, redaction, retry-loop guards.
- Performance-sensitive state reducers/mappers where deterministic tests catch regressions cheaply.
Doubles
- Prefer fakes for repositories/data sources.
- Use stubs for simple fixed responses.
- Use mocks only when interaction is the tested behavior.
- Avoid real network/stores/clocks/platform services unless explicitly integration-level.
Refactors/Migrations
- Keep scope narrow.
- Do not keep old/new paths active without feature flag and removal plan.
- Preserve public contracts unless the goal requires breaking change.
- Move in phases: foundation, adoption, lock-in, cleanup.
- Add regression tests for the motivating failure.
- Make duplicate callbacks/retries idempotent.
- Add redacted observability for high-risk transitions when useful.
Review
Lead reviews with:
- missing high-signal tests
- brittle/misplaced tests
- slow/flaky test risks
- platform mismatch in test source sets
- exact validation commands
- residual risk when platform tests cannot run locally