arabic-to-roman

romans_numbers = (
    ('M', 1000),
    ('CM', 900), ('D', 500), ('CD', 400), ('C', 100),
    ('XC', 90), ('L', 50), ('XL', 40), ('X', 10),
    ('IX', 9), ('V', 5), ('IV', 4), ('I', 1)
)

def convert(arabic):
    romans = ''
    for number_roman, number_arabic in romans_numbers:
        while arabic >= number_arabic:
            romans += number_roman
            arabic -= number_arabic
    return romans

# --- tests ---

tests = (
    (499, 'CDXCIX'),

    (1001, 'MI'),
    (1000, 'M'),
    (30, 'XXX'),
    (29, 'XXIX'),
    (6, 'VI'),
    (5, 'V'),
    (4, 'IV'),
)

for roman, arabic in tests:
    print( roman, arabic, convert(roman) == arabic)

'''
499 CDXCIX True
1001 MI True
1000 M True
30 XXX True
29 XXIX True
6 VI True
5 V True
4 IV True
'''