def test_subtract_same_units(self):
"""Subtract amounts having the same units.
"""
# Results in pounds
self.failUnlessEqual(subtract_amount(2, 'pound', 0.5, 'pound'), 1.5)
# Results in ounces
self.failUnlessEqual(subtract_amount(12, 'ounce', 4, 'ounce'), 8.0)
def test_subtract_different_units(self):
"""Subtract amounts having different units.
"""
# Results in pounds
self.failUnlessEqual(subtract_amount(2, 'pound', 4, 'ounce'), 1.75)
self.failUnlessEqual(subtract_amount(2, 'pound', 12, 'ounce'), 1.25)
self.failUnlessEqual(subtract_amount(0.5, 'pound', 4, 'ounce'), 0.25)
# Results in ounces
self.failUnlessEqual(subtract_amount(12, 'ounce', 0.5, 'pound'), 4.0)
