$dog = new Dog();

$dog->fetch('ball') === 'ball'; // true

using Hammock\mock_object_method($dog, 'fetch', $args ==> 'frisbee');

$dog->fetch('ball') === 'frisbee'; // true

$dog = new Dog();

using (Hammock\mock_object_method($dog, 'fetch', $args ==> 'frisbee')) {
	$dog->fetch('ball') === 'frisbee'; // true
} // Original behavior is restored at the end of the `using` block.

$dog->fetch('ball') === 'ball'; // true

$dog = new Dog();

using $fetchMock = Hammock\mock_object_method($dog, 'fetch', $args ==> {
	// Each intercepted argument must be type-asserted.
	// We recommend https://github.com/hhvm/type-assert for this.
	$arg = strval($args[0]);

	if ($arg === 'ball') {
		return 'frisbee';
	}
	
	return $arg;
});

$dog->fetch('ball') === 'frisbee'; // true
$dog->fetch('bone') === 'bone'; // true

// The arguments for each intercepted call can be retrieved later.
$fetchMock->getArgsForCall(0) === vec['ball']; // true
$fetchMock->getArgsForCall(1) === vec['bone']; // true

// The number of calls from the time the function was mocked.
$fetchMock->getNumCalls() === 2; // true

$dog = new Dog();

using $fetchSpy = Hammock\spy_object_method($dog, 'fetch');

$dog->fetch('ball') === 'ball'; // true

$fetchSpy()->getNumCalls() === 1; // true