How to mock based on method parameter - php

Question

One of my stubbed mock objects has a method which will be called twice in a method that I want to test. How can I write the tests so that both branches in my test method will be coveraged? Code sample (The stubbed object is the cache):
public function myMethodToTest($param, $default) {
if ($this->cache->has($param)) {
return 'A';
} else if ($this->cache->has($default)) {
return 'B';
}
}

Answer 1

Lifted from the phpunit documentation, we can start with this example:
public function testObserversAreUpdated()
{
// Create a mock for the Observer class,
// only mock the update() method.
$observer = $this->getMockBuilder('Observer')
->setMethods(array('update'))
->getMock();
// Set up the expectation for the update() method
// to be called only once and with the string 'something'
// as its parameter.
$observer->expects($this->once())
->method('update')
->with($this->equalTo('something'));
// Create a Subject object and attach the mocked
// Observer object to it.
$subject = new Subject('My subject');
$subject->attach($observer);
// Call the doSomething() method on the $subject object
// which we expect to call the mocked Observer object's
// update() method with the string 'something'.
$subject->doSomething();
}
Pay attention to the with() method call. You can use that to specify an expectation that the method will be called with a specific parameter value and dictate what to return when it happens. In your case, you should be able to do something like this:
$cacheStub->method('has')
->with($this->equalTo('testParam1Value'))
->willReturn(true);
Do that in one test, and you'll test one branch of your code. In a separate test, you can set up the mock differently:
$cacheStub->method('has')
->with($this->equalTo('testParam2Value'))
->willReturn(true);
This test will test your other branch. You can combine them into a single test if you like, you may have to recreate the mock in between assertions.
See also this short article that has some alternative ways of calling with() other than $this->equalTo()