public function testAdd() { $price1 = new Price(['EUR' => 20, 'USD' => 10, 'GBP' => 30]); $price2 = new Price(['EUR' => 2, 'USD' => 1, 'CHF' => 3]); $price = $price1->add($price2); $this->assertEquals(22, $price->getAmount('EUR')); $this->assertEquals(11, $price->getAmount('USD')); $this->assertEquals(3, $price->getAmount('CHF')); $this->assertEquals(30, $price->getAmount('GBP')); }