public function testPositivity()
{
$euro1 = Money::fromAmount('100', Currency::fromCode('EUR'));
$euro2 = Money::fromAmount('0', Currency::fromCode('EUR'));
$euro3 = Money::fromAmount('-100', Currency::fromCode('EUR'));
$euro4 = Money::fromAmount('0.0001', Currency::fromCode('EUR'));
$this->assertTrue($euro1->isPositive());
$this->assertFalse($euro1->isNegative());
$this->assertFalse($euro1->isZero());
$this->assertTrue($euro2->isZero());
$this->assertFalse($euro2->isNegative());
$this->assertFalse($euro2->isPositive());
$this->assertTrue($euro3->isNegative());
$this->assertFalse($euro3->isPositive());
$this->assertFalse($euro3->isZero());
$this->assertFalse($euro4->isZero());
}