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Unit Testing Sample

Short and basic introduction to unit testing

by stracker-phil · github.com/stracker-phil/unit-testing-workshop

★ 1stars

Install

Download source zip No release zip yet

This is the repository archive. It installs, but the folder name will carry the branch suffix and updates will not flow.

Install straight from GitHub with WP-CLI:

wp plugin install https://github.com/stracker-phil/unit-testing-workshop/archive/refs/heads/main.zip
No built-in updater. New versions won't appear under Dashboard → Updates. Install new releases yourself, or let Git Updater track the repository.
Readme github.com/stracker-phil/unit-testing-workshop ↗

We can either write working code, or clean code, but not both at the same time.

Testing allows us to make things work, and ensure it stays working as we make it clean.

-- Summary of TDD philosophy by Kent Beck

Sample Code Structure

workshop-plugin/
├── plugin.php                   # Plugin header only
├── src/
│   ├── BookingValidator.php     # Validates booking data
│   └── BookingProcessor.php     # Processes validated bookings
├── tests/
│   ├── phpunit.xml
│   └── (we'll create these together)
├── composer.json
├── CHEATSHEET.md                 # Quick reference (commands, concepts)
└── README.md                     # This file

Workshop Agenda

Preparation

  1. Launch DDEV and verify the site works (before the workshop)
    • ddev start && ddev orchestrate -f
  2. Ensure the website works
  3. Share code-with-me access in Slack

Setup Phase

  1. Review the sample code we'll test
  2. Install PHPUnit
    • composer require --dev phpunit/phpunit:~9.6.0
  3. Setup & confirm it works:
    • Create (copy) the phpunit.xml config file
    • ddev exec vendor/bin/phpunit

Manual Testing Basics

  1. Write and run first test
    • tests/BookingValidatorTest.php
    • ddev exec vendor/bin/phpunit
  2. Add composer script
    • "test": "vendor/bin/phpunit"
  3. 💬 What makes a good unit test?
    • Isolation (mock everything except the tested class)
    • Stubs vs Mocks (when to use each)
    • One assertion per test (or use dataProviders)
    • Descriptive test names (i.e. documentation)
    • Avoid DRY/abstractions (linear and transparent behavior)

Code Coverage

  1. 💬 Who is using coverage reports already?
  2. Install coverage tool
    • composer require --dev phpmetrics/phpmetrics:^2.9
  3. Configure coverage in phpunit.xml
  4. Generate coverage report
    • ddev exec vendor/bin/phpunit --coverage-html coverage/
    • Add composer script for convenience
  5. Open coverage/index.html in browser
  6. Identify untested code paths
  7. Write one more test to improve coverage

AI-Assisted Testing

  1. Use Claude to generate remaining tests, using MCP
  2. 💬 Review AI-generated code quality together
    • Focus on: Which tests are useless, what can we delete?
  3. Iterate: Ask Claude to refactor/improve the tests
  4. Run full suite → confirm high coverage

Discussion

💬 / review the Claude project at the bottom

Key Takeaways

Three-Step Workflow:

  1. Manual - Establish pattern (1-2 tests)
  2. AI Generate - Bulk structure (10-15 tests in seconds)
  3. Human Refine - Delete trivia, consolidate, focus on behavior

Test coverage reveals risk areas

Claude Project

https://claude.ai/project/01987bbe-7203-7080-a49b-4517ec5a1440

Has a clear understanding of good testing philosophy, and includes capabilities for

  • Interactive coach ("What is a good unit test?")
  • Create uniform test suites for uploaded/copy-pasted code
  • Identify testing gaps (provide test file + covered class)
  • Refactor/improve existing tests ("Review and improve the following test suite...")
  • TDD without MCP (AI writes test in chat, you copy-paste tests and write code)
  • TDD with MCP ("Let's start a TDD session", AI writes test files, you write code)