def test_discount_as_negative_for_zero_value():
discount = Money(0, "USD")
result = discount_as_negative(discount)
assert result == "$0.00"
def test_discount_as_negative_for_html():
discount = Money(10, "USD")
result = discount_as_negative(discount, True)
assert result == '-<span class="currency">$</span>10.00'
def test_discount_as_negative():
discount = Money(10, "USD")
result = discount_as_negative(discount)
assert result == "-$10.00"
