Money\MoneyTest::testSubtraction PHP Method

    public function testSubtraction()
    {
        $m1 = Money::fromAmount('100', Currency::fromCode('EUR'));
        $m2 = Money::fromAmount('200', Currency::fromCode('EUR'));
        $diff = $m1->subtract($m2);
        $expected = Money::fromAmount('-100', Currency::fromCode('EUR'));
        $this->assertTrue($diff->equals($expected));
        // Should return a new instance
        $this->assertNotSame($diff, $m1);
        $this->assertNotSame($diff, $m2);
    }