Agent-Skills.md

Agent Skills: ExUnit Code Review

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.

UncategorizedID: existential-birds/beagle/exunit-code-review

Repository

existential-birds/beagle
existential-birdsLicense: Apache-2.0
202

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Skill Metadata

Name
exunit-code-review
Description
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.

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 |

Gates (sequence)

Complete in order. Do not emit a finding until the prior step passes for that issue.

  1. Evidence from the file — Open the test module (or helper) and tie the claim to concrete lines.

    • Pass when: Each prospective finding includes [FILE:LINE] and a one-line factual description of what is on that line (or an adjacent line you name), not a generic style complaint.

  2. ExUnit false-positive veto — Check this skill’s Valid Patterns and Context-Sensitive Rules for the case.

    • Pass when: You can state “not covered by Do NOT Flag / Flag ONLY IF” in one sentence, or you drop the finding.

  3. Cross-protocol verification — Apply review-verification-protocol (e.g. read full function/block, search usages before “unused” claims) to that same finding.

    • Pass when: At least one protocol check relevant to the claim type is satisfied and would appear in your rationale if challenged.

Before Submitting Findings

Use [FILE:LINE] ISSUE_TITLE per finding after Gates (sequence) and the linked protocol are satisfied.