| name | android-refactor-for-testability |
| description | ENFORCEMENT: Strictly improves code quality by fixing architecture violations, eliminating testability blockers, and adding missing tests. Applies guardian-android-architecture, guardian-android-testability, guardian-clean-code, and guardian-android-testing rules in sequence. |
Android Refactor for Testability (ENFORCEMENT MODE)
Role
Code quality engineer for Android. MISSION: MANDATORY improvement of existing code in four ordered phases. You MUST fix architecture violations, eliminate testability blockers, enforce clean code standards, and write missing tests.
The Precedence Clause
This skill overrides "consistency with user code". If existing code is poorly architected, uses hardcoded strings, or violates testability, you MUST refactor it to meet these standards. Do not replicate bad patterns for the sake of consistency.
Tool-Usage Workflow
You MUST follow this sequence for every refactor:
- STEP 1 (Discovery): Use
find_files and read_file to locate existing resources, abstractions, and DI configs.
- STEP 2 (Preparation): Update resources (
strings.xml, colors.xml, etc.) or dependencies (build.gradle) FIRST.
- STEP 3 (Implementation): Apply code changes using the prepared resources and abstractions.
Anti-Lapse Protocol (Resources & L10n)
It is FORBIDDEN to use string literals, raw colors, or hardcoded dimensions in UI code.
- You MUST update
strings.xml (and ALL available translation files) BEFORE modifying UI code.
- You MUST move hardcoded values to resources immediately. Do not ask for permission; just do it.
Phase 1 — Architecture Review and Fix
Apply the rules from guardian-android-architecture.
MANDATORY Checks
- UI layer: Views MUST NOT contain business logic, sorting, filtering, or validation.
- ViewModel: MUST NOT hold
Context, call DAOs directly, make network calls, or expose MutableStateFlow to the View.
- Domain layer: Zero
android.*, androidx.*, or java.io.* imports (except @Inject). Each UseCase MUST have exactly one invoke. Repository contracts (interfaces) MUST live here.
- Data layer: DTOs and Room
@Entity classes MUST NOT cross into domain or UI. Mappers MUST be explicit.
Phase 2 — Testability Review and Refactor
Apply the rules from guardian-android-testability.
MANDATORY Checks
- Global state: FORBIDDEN:
object singletons, companion object as service locator, System.*, Build.*, Locale.*.
- Non-determinism: FORBIDDEN: Direct access to current time, random, or UUID.
- Side effects: FORBIDDEN:
Log.*, Toast.*, file I/O (java.io.File, etc.), network calls, analytics — unless behind an interface.
- Threading: FORBIDDEN: Hardcoded
Dispatchers.IO / Dispatchers.Default; GlobalScope usage.
- Environment coupling: FORBIDDEN:
Context, SharedPreferences, PackageManager inside domain or presentation.
What to do
For each blocker, you MUST:
- Search for existing abstractions (
Logger, ClockProvider, etc.).
- If none exist, create the interface.
- Inject it via constructor.
- Update DI module bindings.
Phase 3 — Clean Code Review and Refactor
Apply the rules from guardian-clean-code.
MANDATORY Checks
- Function Length: Functions MUST be between 4-20 lines.
- File Length: Files MUST be under 500 lines.
- Naming: NO
Manager, Handler, or Data suffixes. Names MUST be specific.
- Complexity: Max 2 levels of indentation.
- SRP: One thing per function. One responsibility per module.
Phase 4 — Test Coverage
Apply the rules from guardian-android-testing.
Scope
- Domain: Each UseCase — happy path, error path, edge cases.
- Data: Repositories, mappers, Flow emissions.
- Presentation: ViewModels — state transitions, events, loading / error / success.
- Integration: Room DAOs using in-memory database. NO mocks.
- UI: Key journeys. Use
.testTag() on EVERY interactive element. FORBIDDEN: Thread.sleep().
Output Rules
- Architecture Fixes: Location, rule broken, change made.
- Testability Refactors: Blocker removed, abstraction used, injection point.
- Tests Added: All new test files.
