php-testing-patterns

Skill Directory

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PHP Testing Patterns

PHPUnit, WordPress, and WooCommerce testing patterns. For shared test quality principles (philosophy, smells, mocking decisions), see testing-patterns.

Reference Routing

| Need | Reference File | Sections to Read | |------|---------------|-----------------| | PHPUnit + WordPress + WooCommerce patterns | $SKILL_DIR/../testing-patterns/references/phpunit-patterns.md | Full file (~422L, manageable) | | Behavior vs implementation | $SKILL_DIR/../testing-patterns/references/test-philosophy.md | ## The Fundamental Shift + ## Four Core Principles | | Flaky/brittle tests | $SKILL_DIR/../testing-patterns/references/test-smells.md | ## The Six Major Test Smells (relevant subsection) | | Mock usage decisions | $SKILL_DIR/../testing-patterns/references/mocking-strategies.md | ## The Mocking Decision Framework | | AAA pattern/naming | $SKILL_DIR/../testing-patterns/references/test-structure.md | ## The AAA Pattern + ## Test Naming Conventions | | Test data strategy | $SKILL_DIR/../testing-patterns/references/test-data.md | ## Factories + ## Builders |

How to read sections: Grep for heading to find line number, Read with offset+limit.

PHP Assertion Quick Reference

| Use | Instead Of | Why | |-----|-----------|-----| | assertSame($expected, $actual) | assertEquals() | Strict type comparison — assertEquals('1', 1) passes silently | | assertCount(3, $items) | assertSame(3, count($items)) | Better failure messages | | assertInstanceOf(Foo::class, $obj) | assertTrue($obj instanceof Foo) | Better failure messages | | assertStringContainsString() | assertTrue(strpos(...) !== false) | Readable, descriptive | | @dataProvider | Duplicated test methods | DRY, parameterized, each case is a named data set | | $this->factory->post->create() | wp_insert_post() | WordPress factory handles cleanup | | expectException(E::class) | try/catch + fail() | PHPUnit native exception testing |

PHP Red Flags

| Pattern | Why Harmful | Fix | |---------|------------|-----| | assertTrue(true) | No assertion at all | Add meaningful assertion | | assertEquals over assertSame | Type coercion hides bugs | Use assertSame | | Missing @dataProvider | Duplicated test logic | Extract data provider | | Direct DB queries in unit tests | Slow, fragile | Use WordPress factories | | setUp() without parent::setUp() | WP state not initialized | Add parent::setUp() | | Mocking owned classes | Design smell | Refactor for loose coupling | | Missing tearDown() cleanup | State leaks | Restore globals, remove filters | | wp_insert_post() in unit tests | No automatic cleanup | Use $this->factory->post->create() |

WordPress Test Utilities

• WP_UnitTestCase — base class with DB transactions, factory access, assertion helpers
• Factories — $this->factory->post, ->user, ->term, ->comment with create() and create_and_get()
• Brain Monkey — isolate WordPress functions in true unit tests (Functions\when('get_option')->justReturn('value'))
• WC_Unit_Test_Case — WooCommerce base class with product/order helpers