compute the next day | Python Fiddle

### Udacity lesson 2.5, nextDay
###
### Define a simple nextDay procedure, that assumes
### every month has 30 days.
###
### For example:
###    nextDay(1999, 12, 30) => (2000, 1, 1)
###    nextDay(2013, 1, 30) => (2013, 2, 1)
###    nextDay(2012, 12, 30) => (2013, 1, 1)  (even though December really has 31 days)
###

def my_function(year, month, day):
    
    day = day + 1 if day < 30 else 1

if day == 1:
        if month == 12:
            month = 1
        else:
            month = month + 1
    
    year = year + 1 if month == 1 and day == 1 else year

return (year, month, day)

def test():
    test_cases = [
                  ((1,1,1),        (1,1,2)), 
                  ((1999,12,1),        (1999,12,2)), 
                  ((1999,12,29),        (1999,12,30)), 
                  ((1999,12,30),        (2000,1,1)), 
                  ((1999,1,30),        (1999,2,1)) 
                  ]
    passes = 0
    for (args, expected_result) in test_cases:
        result = my_function(*args)
        if result != expected_result:
            print "Failed when argument was: ", args, ".  Expected: ", expected_result, " Got: ", result
        else:
            passes = passes + 1
    print passes, " out of ", len(test_cases), " test cases passed."

test()

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