public function testCanCalculateSurfaceVolumeOfTwoDifferentShapes()
{
$square = new Square(2);
$circle = new Circle(4);
$calculator = new Calculator();
// expected value
$value = $square->volume() + $circle->volume();
$this->assertEquals($value, $calculator->totalVolume(compact('square', 'circle')));
}
public function testVolumeAlwaysReturnsZero()
{
$square = new Square(0);
$this->assertEquals(0, $square->volume());
$square = new Square(2);
$this->assertEquals(0, $square->volume());
$square = new Square(3.14);
$this->assertEquals(0, $square->volume());
}