def test_subtract_different_unit(self):
a = meters(1)
b = kilometers(1)
with self.assertRaises(OperationError):
print(a - b)
def test_add_same_unit(self):
a = meters(1)
b = meters(2)
expected = meters(3)
self.assertEqual(expected, a + b)
def test_subtract_same_unit(self):
a = meters(5)
b = meters(2)
expected = meters(3)
self.assertEqual(expected, a - b)
def test_equal(self):
km_in_m = meters(1000)
km = kilometers(1)
self.assertEqual(km, km_in_m)