ExUnit Code Review

Quick Reference

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: true unless 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
• [ ] verifyonexit! 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

Before Submitting Findings

Use the issue format: [FILE:LINE] ISSUE_TITLE for each finding.

Load and follow review-verification-protocol before reporting any issue.