---
name: php-testing-8e1b707a10e8
description: >
  Write PHP tests with PHPUnit — unit tests, mocking, data providers,
  assertions, test doubles, and TDD workflow. Use when writing tests for
  WooCommerce extensions or PHP projects.
---

# PHP Testing with PHPUnit

## Before writing code

**Fetch live docs**: Web-search `site:phpunit.de documentation` for the latest PHPUnit documentation. Check `https://phpunit.de/` for current version and features.

## PHPUnit Fundamentals

### Test Class Structure

- Extend `PHPUnit\Framework\TestCase` (or `WC_Unit_Test_Case` for WooCommerce)
- Test methods prefixed with `test` or annotated with `#[Test]`
- `setUp()` — runs before each test
- `tearDown()` — runs after each test
- `setUpBeforeClass()` / `tearDownAfterClass()` — run once per class

### Assertions

Core assertions:
- `assertEquals( $expected, $actual )` — loose equality
- `assertSame( $expected, $actual )` — strict identity
- `assertTrue( $condition )` / `assertFalse( $condition )`
- `assertNull( $value )` / `assertNotNull( $value )`
- `assertCount( $expected, $array )`
- `assertContains( $needle, $haystack )`
- `assertInstanceOf( $class, $object )`
- `assertArrayHasKey( $key, $array )`
- `assertStringContainsString( $needle, $haystack )`

### Exception Testing

- `$this->expectException( InvalidArgumentException::class )`
- `$this->expectExceptionMessage( 'Expected message' )`
- `$this->expectExceptionCode( 404 )`

## Test Doubles

### Mocks

Create mock objects to verify interactions:
```php
$mock = $this->createMock( PaymentProcessor::class );
$mock->expects( $this->once() )
     ->method( 'charge' )
     ->with( $this->equalTo( 29.99 ) )
     ->willReturn( true );
```

### Stubs

Return predetermined values without verifying calls:
```php
$stub = $this->createStub( PriceCalculator::class );
$stub->method( 'calculate' )->willReturn( 29.99 );
```

### Expectation Methods

- `$this->once()` — called exactly once
- `$this->exactly( $n )` — called exactly n times
- `$this->never()` — not called
- `$this->atLeastOnce()` — called one or more times
- `$this->any()` — any number of calls

### willReturn Variants

- `willReturn( $value )` — return fixed value
- `willReturnMap( $map )` — return based on arguments
- `willReturnCallback( $callable )` — custom logic
- `willThrowException( $exception )` — throw on call

## Data Providers

### What They Do

Supply multiple test cases to a single test method:

```php
public static function priceProvider(): array {
    return [
        'regular price' => [ 29.99, 29.99, '' ],
        'sale price'    => [ 29.99, 19.99, '19.99' ],
        'zero price'    => [ 0.00, 0.00, '' ],
    ];
}

#[DataProvider('priceProvider')]
public function test_get_display_price( float $regular, float $expected, string $sale ): void {
    // test with each data set
}
```

### Best Practices for Providers

- Name data sets descriptively (keyed array)
- Keep providers as static methods
- Return arrays of arrays (each inner array = one test case)
- Use `#[DataProvider('methodName')]` attribute

## WordPress/WooCommerce Testing Specifics

### WP_UnitTestCase

- Provides WordPress-loaded environment
- Each test wrapped in a database transaction (auto-rollback)
- Factory methods: `$this->factory->post`, `$this->factory->user`
- `go_to( $url )` — simulate page load
- `set_current_screen( 'edit-post' )` — simulate admin screen

### Mocking WordPress Functions

Use `WP_Mock` or `Brain\Monkey` libraries:
- Mock `add_action`, `add_filter`, `do_action`, `apply_filters`
- Mock `wp_remote_get`, `get_option`, etc.
- Useful for isolated unit tests without WordPress bootstrap

### Mocking HTTP Requests

Filter `pre_http_request` to intercept `wp_remote_get()` / `wp_remote_post()`:
```php
add_filter( 'pre_http_request', function( $preempt, $args, $url ) {
    return [ 'response' => [ 'code' => 200 ], 'body' => '{"status":"ok"}' ];
}, 10, 3 );
```

## Test Organization

### Directory Structure

```
tests/
├── bootstrap.php           # Test bootstrap
├── Unit/                   # Pure unit tests (no WP)
│   └── PriceCalculatorTest.php
├── Integration/            # Tests with WP/WC loaded
│   ├── ProductTest.php
│   └── OrderTest.php
└── E2E/                    # Playwright end-to-end
    └── specs/
```

### phpunit.xml.dist Configuration

- Define test suites: `unit`, `integration`
- Set bootstrap file
- Configure coverage report output
- Set environment variables

## TDD Workflow

1. **Red** — write a failing test that describes the desired behavior
2. **Green** — write the minimum code to make the test pass
3. **Refactor** — clean up code while keeping tests green
4. Repeat

## Best Practices

- One assertion per test (when practical)
- Name tests descriptively: `test_process_payment_returns_success_for_valid_card`
- Use data providers for parameterized tests
- Mock external dependencies (APIs, databases, file system)
- Test edge cases: null values, empty strings, boundary values, invalid input
- Keep unit tests fast — no network, no filesystem, no database
- Use integration tests for WordPress/WooCommerce interaction testing
- Run tests in CI on every push

Fetch the PHPUnit documentation for exact assertion signatures, mock API, and configuration options before implementing.


---
Source attribution: OrcaQubits
Original project: https://github.com/OrcaQubits/agentic-commerce-skills-plugins/blob/30cd25c74c8aa7dc49b3ec4847d463f6104439f6/dist/antigravity/woocommerce-commerce/.agent/skills/php-testing/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Mega AI Hub.

## Upstream license notice

MIT License

Copyright (c) 2024-2026 OrcaQubits AI (https://orcaqubits-ai.com)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Mega AI Hub resource metadata

Creator / publisher: OrcaQubits
Original project: https://github.com/OrcaQubits/agentic-commerce-skills-plugins/blob/30cd25c74c8aa7dc49b3ec4847d463f6104439f6/dist/antigravity/woocommerce-commerce/.agent/skills/php-testing/SKILL.md
Attribution basis: Source repository record

Fields of work: Development & Engineering, Product Management
Roles: Backend Developer, Product Manager, QA / Test Engineer
Specialties: Testing
Tools: Phpunit
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: 3b9b0737bc06efe1c153fcde6898d05adedae5f504906baf9d987550cd4dae1b