/tdd-with-phpunit

name: tdd-with-phpunit
description: Apply RED-GREEN-REFACTOR with PHPUnit 10/11 for Symfony; KernelTestCase/WebTestCase, attributes (#[Test]/#[DataProvider]), Foundry
capabilities: [read, search, edit, shell]
tags: [testing, tdd]
# projected by `bun run build` — do not edit by hand
allowed-tools:
  - Read
  - Glob
  - Grep
  - Write
  - Edit
  - Bash

Tdd With Phpunit (Symfony)

Use when

• Driving a feature with RED-GREEN-REFACTOR using PHPUnit 10/11 class-based tests.
• Choosing between `TestCase`, `KernelTestCase` and `WebTestCase` for a new behavior.
• Testing a console command, or an invalid form that must answer 422.
• Swapping an external service for a double through the test container.

Default workflow

1. RED: pick the base class, write the test with `#[Test]`, `#[DataProvider]` and `#[CoversClass]`, run it and check it fails for the right reason. 2. GREEN: write the minimum code that passes. 3. REFACTOR with the suite green, re-running it after each change. 4. Replace an external boundary with `static::getContainer()->set(Service::class, $mock)`. 5. Test commands with `CommandTester`, or with `runCommand()` and `assertCommandIsSuccessful()` on Symfony 8.1+. 6. Assert invalid form submissions with `assertResponseIsUnprocessable()`.

Guardrails

• Use PHPUnit 10+ attributes, not `@test` or `@dataProvider` annotations.
• Fetch services with `static::getContainer()`, not the legacy `self::$container`.
• Mock only true external boundaries (HTTP clients, third-party SDKs); keep real services and a real database elsewhere.
• `runCommand()` and closures in `getContainer()->set()` need Symfony 8.1+.

Progressive disclosure

• Use this file for execution posture and risk controls.
• Open references when deep implementation details are needed.

Output contract

• The failing PHPUnit output (RED), then the passing run.
• Test files changed, with the base class and attributes used.
• Commands executed.

References

• `reference.md`