def __add__(self, other):
"""Add own quantity with other's.
"""
obj, other = convert_to_correct_unit(self, other)
quantity_result = add_quantities_with_units(obj, other)
self.quantity = quantity_result
def __sub__(self, other):
"""Decrease own quantity with other's.
Returns True if this amount is no longer usable.
"""
obj, other = convert_to_correct_unit(self, other)
quantity_result = sub_quantities_with_units(obj, other)
self.quantity = quantity_result
return quantity_result <= 0
def test_convert_volume_to_unit(self):
""" When converting 2L to unit with avg_unit_volume=1L, should return 2"""
item = InventoryItem.objects.create(place=self.place,
product=self.leche_descremada,
quantity=2,
unit=Unit.objects.get(name='unit'))
amount = Amount(unit=Unit.objects.get(short_name='L'), quantity=2)
obj, other = convert_to_correct_unit(item, amount)
self.assertEqual(round(other.magnitude), 2)
self.assertEqual(round((obj - other).magnitude), 0)
def test_convert_mass_to_unit(self):
""" When converting 2kg to unit with avg_unit_weight=0.252kg, should return ~8"""
item = InventoryItem.objects.create(place=self.place,
product=self.manzana,
quantity=2,
unit=Unit.objects.get(name='unit'))
amount = Amount(unit=Unit.objects.get(short_name='kg'), quantity=2)
obj, other = convert_to_correct_unit(item, amount)
self.assertEqual(round(other.magnitude), 8)
self.assertEqual(round((obj - other).magnitude), -6)
def test_convert_unit_to_mass(self):
""" When converting 1unit to g with avg_unit_weight=0.252kg, should return 252g"""
item = InventoryItem.objects.create(
place=self.place,
product=self.manzana,
quantity=1000,
unit=Unit.objects.get(short_name='g'))
amount = Amount(unit=Unit.objects.get(name='unit'), quantity=1)
obj, other = convert_to_correct_unit(item, amount)
self.assertEqual(round(other.magnitude), 252)
self.assertEqual(round((obj - other).magnitude), 748)
def test_convert_volume_with_density_to_mass(self):
""" When converting 0.4845L to kg with density=1032kg/m**3, should return 0.5kg"""
item = InventoryItem.objects.create(
place=self.place,
product=self.leche,
quantity=5,
unit=Unit.objects.get(short_name='kg'))
amount = Amount(unit=Unit.objects.get(short_name='L'), quantity=0.4845)
obj, other = convert_to_correct_unit(item, amount)
self.assertEqual(round(other.magnitude, 1), 0.5)
self.assertEqual(round((obj - other).magnitude, 1), 4.5)
def test_convert_mass_with_density_to_volume(self):
""" When converting 2064g to L with density=1032kg/m**3, should return 2L"""
item = InventoryItem.objects.create(
place=self.place,
product=self.leche,
quantity=5,
unit=Unit.objects.get(short_name='L'))
amount = Amount(unit=Unit.objects.get(short_name='g'), quantity=2064)
obj, other = convert_to_correct_unit(item, amount)
self.assertEqual(round(other.magnitude), 2)
self.assertEqual(round((obj - other).magnitude), 3)
def add(self, other):
"""Incrase own quantity with other's."""
self_qu, other_qu = convert_to_correct_unit(self, other)
return add_quantities_with_units(self_qu, other_qu)
def substract(self, other):
"""Decrease own quantity with other's."""
self_qu, other_qu = convert_to_correct_unit(self, other)
return sub_quantities_with_units(self_qu, other_qu)
