/** * */ public function testIncrementAge() { //Create an Object to test with. //We're creating an Animal object because the tested functionality is inherited by 'Dog' and 'Cat' $animal = new Animal('Animal', 1); //Speak once $animal->speak("test"); //Our age should still be 1 $this->assertEquals(1, $animal->age()); //Speak twice $animal->speak("test"); //Now our age should be 2 $this->assertEquals(2, $animal->age()); }