Unit Tests Demo

class.stephanis-addition.php

<?php

class StephanisAddition {
	public static function add_two_numbers( $number_one, $number_two ) {
		if ( ! is_numeric( $number_one ) || ! is_numeric( $number_two ) ) {
			return null;
		}

		return $number_one + $number_two;
	}
}

test-class.stephanis-addition.php

<?php

include 'class.stephanis-addition.php';

class StephanisAdditionTest extends PHPUnit_Framework_TestCase {

	public function test_adding_two_numbers() {
		$this->assertEquals( 12, StephanisAddition::add_two_numbers( 5, 7 ) );
	}

	public function test_rejection_of_non_numbers() {
		$this->assertNull( StephanisAddition::add_two_numbers( 'Blue', 7 ) );
		$this->assertNull( StephanisAddition::add_two_numbers( 7, 'Pink' ) );
		$this->assertNull( StephanisAddition::add_two_numbers( 'Blue', 'Pink' ) );
	}

}