public function testSub()
{
$tests = [[Distance::m(1000)->sub(Distance::km(1))->m, 0], [Distance::km(10)->sub(Distance::m(200))->m, 9800]];
foreach ($tests as $test) {
$this->assertEquals($test[1], $test[0]);
}
}
public function testShouldConvertToKilometersWithAlias()
{
$distance = new Distance(1000);
$this->assertSame(1.0, $distance->km());
}