mozilla FXA Test Repair
Review a test file for violations of the FXA testing guidelines and produce a prioritized repair plan with before/after code suggestions. This skill does not modify files — all repairs are presented for engineer review for correctness and scope before implementation.
If scope of changes is large, suggest a reasonable subset of repairs to implement in a single pass to avoid overwhelming diffs and code review. Always prioritize correctness and test value over style — if a repair improves readability but risks changing test behavior, flag it as Medium severity and note the risk.
Read the testing rules before proceeding: .claude/rules/testing/base.md (general FXA test rules). The rule also auto-loads when Claude reads the target test file, but reading it explicitly here ensures the audit covers every rule even before the file is opened.
If the target file is a React component test (*.test.tsx), also read .claude/rules/testing/react.md and audit against those component-test rules in addition.
Step 1: Identify the Target File
If $ARGUMENTS is provided, use it as the test file path.
Otherwise check for recently changed test files:
git diff HEAD --name-only | grep -E '\.(spec|test)\.(ts|tsx)$'
git diff --cached --name-only | grep -E '\.(spec|test)\.(ts|tsx)$'
If multiple files are found, ask the engineer which to repair. If none, ask explicitly.
Step 2: Read the File
Read the full test file. Note:
- Total number of tests
- Testing framework (Jest vs Mocha — flag Mocha, no new tests should be added)
- How mocks are structured (module-level,
beforeEach, inline) - Whether shared state variables exist at module or
describescope
Step 3: Audit for Violations
Work through every rule in the shared guidelines. For each violation found, record: location, the rule it breaks, and a before/after repair snippet. If a rule has no violations, note it as clean — do not skip rules.
Step 4: Present the Repair Plan
Output a prioritized findings table:
| # | Severity | Rule violated | Location | Description |
|---|---|---|---|---|
| 1 | High | Independent & order-agnostic | account.spec.ts:14 |
account mutated across tests without beforeEach reset |
| 2 | Medium | Assert explicitly | account.spec.ts:42 |
toBeTruthy() used where exact value is known |
| 3 | Low | Independent & order-agnostic | account.spec.ts:8 |
jest.clearAllMocks() in beforeEach redundant — this package's jest.config.* already sets clearMocks: true (only flag when verified against the project config) |
Severity:
- High — likely causes false positives, order-dependent failures, or masks real regressions (shared mutable state, missing
await, over-mocking) - Medium — reduces test value or maintainability (vague assertions, non-deterministic values, implementation-detail testing)
- Low — noise or convention violations that don't affect correctness (redundant calls, vague names, minor patterns)
Follow the table with a detailed write-up for each High finding, including a before/after code snippet showing the repair.
For Medium and Low findings, a one-line description and the repair snippet is sufficient.
Step 5: Suggest Scope
After presenting findings, suggest a reasonable repair scope based on the volume of issues:
- Few issues (1–5): Suggest fixing all in one pass.
- Moderate (6–15): Suggest prioritizing High findings first; Medium/Low in a follow-up.
- Many (16+): Suggest tackling by rule category across the file rather than line-by-line, and note that
/fxa-test-independenceshould be run after repairs to validate nothing regressed.
Remind the engineer: repairs are suggestions. Review each one — especially mock restructuring, which can change test behavior, not just style.