PHPUnit: get arguments to a mock method call

Here's the trick I used. I added this private method to my test class:

private function captureArg( &$arg ) {
    return $this->callback( function( $argToMock ) use ( &$arg ) {
        $arg = $argToMock;
        return true;
    } );
}

Then when setting up the mock:

$mock->expects( $this->once() )
    ->method( 'someMethod' )
    ->with( $this->captureArg( $arg ) );

After that, $arg contains the value of the argument passed to the mock.

One thing - inside the closure you still can access $this, in that case it gives you:

$this->patientDao
    ->expects($this->once()) 
    ->method('savePatient')
    ->will($this->returnCallback(function($patient) {
        $this->assertNull($patient->getPhoneNumber());
    }));

Make the Mock objects method return the first argument:

$this->patientDao                    // This is my mock
            ->expects($this->once()) 
            ->method('savePatient') // savePatient() must be called once
            ->with($this->returnArgument(0));

You can then assert that it is NULL.

You can make assertions on the argument using returnCallback(). Remember to call assert functions statically via PHPUnit_Framework_Assert because you cannot use self inside a closure.

$this->patientDao
        ->expects($this->once()) 
        ->method('savePatient')
        ->will($this->returnCallback(function($patient) {
            PHPUnit_Framework_Assert::assertNull($patient->getPhoneNumber());
        }));