public function testFindsTheDifferenceOfNumbers()
 {
     $subtraction = new Subtraction();
     $difference = $subtraction->run(5, 0);
     $this->assertEquals(-5, $difference);
 }
 public function testSubtractsNumbers()
 {
     $subtraction = new Subtraction();
     $result = $subtraction->run(5, 10);
     $this->assertSame(5, $result);
 }