Unit Testing in PHP: PHPUnit Best Practices

Unit testing ensures that your PHP code behaves as expected. PHPUnit is the standard library for unit testing in PHP projects.

Basic Test Structure

use PHPUnit\Framework\TestCase;

class CalculatorTest extends TestCase {
    public function testAddition() {
        $calc = new Calculator();
        $this->assertEquals(4, $calc->add(2, 2));
    }
}

Mocking Dependencies

Use mocks to isolate the unit under test:

$serviceMock = $this->createMock(UserService::class);
$serviceMock->method('getUser')->willReturn(new User('Alice'));

Test Organization

• Group tests by feature or service
• Follow AAA pattern: Arrange, Act, Assert
• Use data providers for repeated scenarios

Continuous Integration

Integrate PHPUnit tests into CI pipelines to catch regressions early.

Conclusion

Adopting a strong unit testing strategy in PHP improves code quality, maintainability, and reduces bugs in production.