exunit-code-review

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Translated

Reviews ExUnit test code for proper patterns, boundary mocking with Mox, and test adapter usage. Use when reviewing _test.exs files or test helper configurations.

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Sourceexistential-birds/beagle

Added on2026-02-09

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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: 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
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.