tools-only ExUnit Code Review
Quick Reference
| Issue Type | Reference |
|---|---|
| Async tests, setup, describe, tags | references/exunit-patterns.md |
| Behavior-based mocking, expectations | references/mox-boundaries.md |
| Bypass, Swoosh, Oban testing | references/test-adapters.md |
| What to mock vs real, Ecto sandbox | references/integration-tests.md |
Mock Boundary Philosophy
Mock at external boundaries:
- HTTP clients, external APIs, third-party services
- Slow resources: file system, email, job queues
- Non-deterministic: DateTime.utc_now(), :rand
DO NOT mock internal code:
- Contexts, schemas, GenServers
- Internal modules, PubSub
- Anything you wrote
Review Checklist
Test Structure
- Tests are
async: trueunless sharing database state - Describe-blocks group related tests
- Setup extracts common test data
- Tests have clear arrange/act/assert structure
Mocking
- Mox used for external boundaries (HTTP, APIs)
- Behaviors defined for mockable interfaces
- No mocking of internal modules
- verify_on_exit! in setup for strict mocking
Test Adapters
- Bypass for HTTP endpoint mocking
- Swoosh.TestAdapter for email testing
- Oban.Testing for background job assertions
Database
- Ecto.Adapters.SQL.Sandbox for isolation
- Async tests don't share database state
- Fixtures/factories used consistently
Valid Patterns (Do NOT Flag)
- Mock in unit test, real in integration - Different test levels have different needs
- Not mocking database in integration tests - Database is internal
- Simple inline test data - Not everything needs factories
- Testing private functions via public API - Correct approach
Context-Sensitive Rules
| Issue | Flag ONLY IF |
|---|---|
| Not async | Test actually needs shared state |
| Missing mock | External call exists AND no mock/bypass |
| Mock internal | Module being mocked is internal code |
Before Submitting Findings
Use the issue format: [FILE:LINE] ISSUE_TITLE for each finding.
Load and follow review-verification-protocol before reporting any issue.