Can I change a method on a PHPUnit Mock after I've set it?

Question

I'm trying to create a mock instance in setUp with default values for all of the overridden methods and then in several different tests change the return value for some of the methods depending on what I'm testing without having to set up the entire Mock. Is there a way to do this?

This is what I tried, but the naive approach doesn't work. The method still returns the value from the original expectation setup.

First setup:

$my_mock->expects($this->any())
        ->method('one_of_many_methods')
        ->will($this->returnValue(true));

In another test before a different assert:

$my_mock->expects($this->any())
        ->method('one_of_many_methods')
        ->will($this->returnValue(false));

Duplicate to this question: PHPUnit Mock Change the expectations later, but that one got no responses and I thought a new question might bring the issue to the fore.

Answer 1

In cases where you use the same method more than once, you should use the "at" declaration with the proper count where executed in the code. This way PHPUnit knows which one you mean, and can fulfill the expectation/assertion properly.

The following is a generic example where method 'run' is used several times:

public function testRunUsingAt()
    {
        $test = $this->getMock('Dummy');

        $test->expects($this->at(0))
            ->method('run')
            ->with('f', 'o', 'o')
            ->will($this->returnValue('first'));

        $test->expects($this->at(1))
            ->method('run')
            ->with('b', 'a', 'r')
            ->will($this->returnValue('second'));

        $test->expects($this->at(2))
            ->method('run')
            ->with('l', 'o', 'l')
            ->will($this->returnValue('third'));

        $this->assertEquals($test->run('f', 'o', 'o'), 'first');
        $this->assertEquals($test->run('b', 'a', 'r'), 'second');
        $this->assertEquals($test->run('l', 'o', 'l'), 'third');
    }

I think this is what you're looking for, but if I'm misunderstanding please let me know.

Now in terms of mocking anything, you can mock it as many times as you want, but you are not going to want to mock it with the same name as in the setup, else every time you use it you are referring to the setup. If you need to test similar methods in different scenarios, then mock it for each test. You could create one mock in the setup, yet for one test use a different mock of a similar item within an individual test, but not of the global name.

Answer 2

You could do this using a lambda callback:

$one_of_many_methods_return = true;
$my_mock->expects($this->any())
        ->method('one_of_many_methods')
        ->will(
             $this->returnCallback(
                 function () use (&$one_of_many_methods_return) {
                     return $one_of_many_methods_return;
                 }
              )         
          );
$this->assertTrue($my_mock->one_of_many_methods());

$one_of_many_methods_return = false;

$this->assertFalse($my_mock->one_of_many_methods());    

Note the & in the use statement.

Answer 3

I have not tried this, but could you not set the Mock up in the Setup, then in each of the tests:

public function testMethodReturnsTrue
{
    $this->my_mock->will($this->returnValue(true));
    $this->assertTrue( ... );
    ...
}

I am not sure if this will work, as I am trying to set the will() method in the test, not when the initial mock was created.

Answer 4

Rather than trying to override mocked methods, I find it easier to override the mocked objects themselves. For example:

class ThingTest extends \PHPUnit_Framework_TestCase
    public function setUp()
    {
        $this->initFoo();
        $this->initBar();
    }

    public function testOne()
    {
        // Uses default [method => value] map for foo and bar
        $this->assertSomething($this->thing->someMethod());
    }

    public function testTwo()
    {
        // Override foo's map
        $this->initFoo(['method1' => 'some other value']);
        $this->assertSomethingElse($this->thing->someMethod());
    }

    public function testThree()
    {
        // Override bar explicitly, so we can use 'once'
        $this->initBar([]);
        $this->bar->expects($this->once())
                  ->method('method1');
        $this->thing->someOtherMethod();
    }

    private function initFoo($methods = null)
    {
        $this->init('foo',
                    $this->getMock('Foo'),
                    is_null($methods)? ['method1' => 'default value 1']
                                    : $methods);
    }

    private function initBar($methods = null)
    {
        $this->init('bar',
                    $this->getMock('Bar'),
                    is_null($methods)? ['method1' => 'default value 1']
                                     : $methods);
    }

    private function init($name, $object, $methods)
    {
        $this->$name = $object;
        foreach ($methods as $method => $value) {
            $this->$name->expects($this->any())
                        ->method($method)
                        ->will($this->returnValue($value));
        }
        $this->thing = new Thing($this->foo, $this->bar);
    }
}

Answer 5

You can also run the tests in a separate process:

/**
 * @runTestsInSeparateProcesses b/c we change the return value of same expectation
 * @see http://stackoverflow.com/questions/13631855
 */
class ThingTest extends \PHPUnit_Framework_TestCase
{
    public function setUp() {
        $this->config = Mockery::mock('alias:Config');
    }

    public function test_thing_with_valid_config() {
        $this->config_set('default', 'valid');
        $sut = new \Thing();
    }

    /**
     * @dataProvider provides_broken_configs
     * @expectedException \RuntimeException
     */
    public function test_thing_with_broken_config($default) {
        $this->config_set('default', $default);
        $sut = new \Thing();
    }

    public function provides_broken_configs() {
        return [ [ null ] ];
    }

    protected function config_set($key, $value) {
        $this->config->shouldReceive('get')->with($key)->andReturn($value);
    }
}

In this example, I happen to be using Mockery, but the pattern is the same. Because each test has fresh memory each run through, we don't encounter the limitation of "overriding" previously set expectations.