What are some common pitfalls to avoid when implementing unit testing in PHP?

One common pitfall to avoid when implementing unit testing in PHP is relying too heavily on mocking external dependencies. While mocking can be useful for isolating the unit under test, overusing it can lead to overly complex and brittle tests. It's important to strike a balance between mocking and testing real behavior to ensure that your tests accurately reflect the behavior of your code. 

// Avoid relying too heavily on mocking external dependencies
// Strike a balance between mocking and testing real behavior

// Bad example: Overusing mocks
$dependencyMock = $this->getMockBuilder(Dependency::class)
    ->disableOriginalConstructor()
    ->getMock();

$dependencyMock->expects($this->once())
    ->method('someMethod')
    ->willReturn('mocked value');

$myClass = new MyClass($dependencyMock);

// Good example: Testing real behavior
$dependency = new Dependency();
$myClass = new MyClass($dependency);

$this->assertEquals('expected value', $myClass->someMethod());

Keywords

mocking PHPUnit code coverage dependency injection test doubles

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