def test_roman_invalid(self):
result, _, is_valid = convert('IC')
assert result == 'Not a valid roman number'
assert is_valid is False
def test_gibberish(self):
result, _, is_valid = convert('k')
assert result == 'Cannot evaluate expression'
assert is_valid is False
def test_roman_max(self):
result, _, is_valid = convert('MMMCMXCIX')
assert result == '3999'
assert is_valid
def test_roman_small_letters(self):
result, _, is_valid = convert('iii')
assert result == '3'
assert is_valid
def test_roman_min(self):
result, _, is_valid = convert('I')
assert result == '1'
assert is_valid
def test_num_greater(self):
result, _, is_valid = convert('4000')
assert result == 'Numbers greater than 3999 are not represented'
assert is_valid is False
def test_num_max(self):
result, _, is_valid = convert('3999')
assert result == 'MMMCMXCIX'
assert is_valid
def test_num_min(self):
result, _, is_valid = convert('1')
assert result == 'I'
assert is_valid
def test_num_less(self):
result, _, is_valid = convert('0')
assert result == "Can't convert 0 and negative numbers"
assert is_valid is False