def test_from_db_value_checks_currency():
field = PriceField('price',
currency='BTC',
default='5',
max_digits=9,
decimal_places=2)
invalid = Price(1, currency='USD')
with pytest.raises(ValueError):
field.from_db_value(invalid, None, None, None)
def test_from_db_value_handles_none():
field = PriceField('price',
currency='BTC',
default='5',
max_digits=9,
decimal_places=2)
assert field.from_db_value(None, None, None, None) is None
