Comparison with PHPUnit mocks

Now that we saw how you can use prophecy as a start, let's compare it with the other frequently used PHPUnit mocking framework.

$mock
  ->expects($this->atLeastOnce())
  ->method('get')
  ->with('param1', 'param2')
  ->willReturnValue('some return value');

$prophecy
  ->get('param1', 'param2')
  ->willReturn('some return value');

 $mock
  ->expects($this->any())
  ->method('get')
  ->willReturnMap([
    ['key1', 'return value 1'],
    ['key2', 'return value 2'],
  ]);

$prophecy
  ->get('key1')
  ->willReturn('return value 1');
$prophecy
  ->get('key2')
  ->willReturn('return value 2');

// @todo Pending.

// @todo Pending.

PHPUnit expectations always add an assert while Prophecy does not. A real equivalent would be $prophecy->get('param1', 'param2')->willReturn('some return value')->shouldBeCalled(). If the return value is not asserted directly or indirectly (ie. if the tested code does not use it) a shouldBeCalled() or similar prediction is an absolute must. For example:

class ImageOperation {
  public function __construct(Image $image) {
    $this->image = $image;
  }

  public function shrinkAndDesaturate() {
    $this->image->crop(50, 50);
    // Oops! We accidently left this commented out.
    //$this->image->desaturate();
  }
}

class ImageTest extends UnitTestCase {
  public function testShrinkAndDesaturate() {
    $image = $this->prophesize(Image::class);
    $image->crop(50, 50)->willReturn(TRUE);
    $image->desaturate()->willReturn(FALSE);
    $op = new ImageOperation($image->reveal());

    // Since there is no shouldBeCalled() prediction for the each method call, this test
    // will pass, even though it should fail since there was no desaturate() call.
    $op->shrinkAndDesaturate();
  }
}