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)
