def test_check_four_digits_five_thousand(self): self.assertEqual(check_four_digits(5000), 'MMMMM')
def test_check_four_digits_nine_hundred(self): self.assertEqual(check_four_digits(900), 'CM')
def test_check_four_digits_one_thousand(self): self.assertEqual(check_four_digits(1000), 'M')
def test_check_four_digits_five_hundred(self): self.assertEqual(check_four_digits(500), 'D')
def test_check_four_digits_one(self): self.assertEqual(check_four_digits(1), 'I')
def test_check_four_digits_six(self): self.assertEqual(check_four_digits(6), 'VI')
def test_check_four_digits_four_hundred(self): self.assertEqual(check_four_digits(400), 'CD')
def test_check_four_digits_ninety(self): self.assertEqual(check_four_digits(90), 'XC')
def test_check_four_digits_ninety_nine(self): self.assertEqual(check_four_digits(99), 'XCIX')
def test_check_four_digits_fifty(self): self.assertEqual(check_four_digits(50), 'L')
def test_check_four_digits_sixty(self): self.assertEqual(check_four_digits(60), 'LX')
def test_check_four_digits_forty(self): self.assertEqual(check_four_digits(40), 'XL')
def test_check_four_digits_twenty(self): self.assertEqual(check_four_digits(20), 'XX')
def test_check_four_digits_ten(self): self.assertEqual(check_four_digits(10), 'X')
def test_check_four_digits_nine_thousand_nine_hundred_ninety_nine(self): self.assertEqual(check_four_digits(9999), 'MMMMMMMMMCMXCIX')
def test_check_four_digits_one_hundred(self): self.assertEqual(check_four_digits(100), 'C')
def test_check_four_digits_four(self): self.assertEqual(check_four_digits(4), 'IV')
def test_check_four_digits_five(self): self.assertEqual(check_four_digits(5), 'V')