finds total days between given dates

Udacity Data Structure and Algorithms Nanodegree/Introduction/daysBetweenDates.py

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+# Define a daysBetweenDates procedure that would produce the
+# correct output if there was a correct nextDay procedure.
+#
+# Note that this will NOT produce correct outputs yet, since
+# our nextDay procedure assumes all months have 30 days
+# (hence a year is 360 days, instead of 365).
+#
+
+def nextDay(year, month, day):
+    """Simple version: assume every month has 30 days"""
+    if day < 30:
+        return year, month, day + 1
+    else:
+        if month == 12:
+            return year + 1, 1, 1
+        else:
+            return year, month + 1, 1
+
+
+def dateIsBefore(year1, month1, day1, year2, month2, day2):
+    if year1 < year2:
+        return True
+    if year1 == year2:
+        if month1 < month2:
+            return True
+        if month1 == month2:
+            return day1 < day2
+
+    return False
+
+
+def daysBetweenDates(year1, month1, day1, year2, month2, day2):
+    """Returns the number of days between year1/month1/day1
+       and year2/month2/day2. Assumes inputs are valid dates
+       in Gregorian calendar, and the first date is not after
+       the second."""
+
+    # YOUR CODE HERE!
+    days = 0
+    while dateIsBefore(year1, month1, day1, year2, month2, day2):
+        year1, month1, day1 = nextDay(year1, month1, day1)
+        days += 1
+
+    return days
+
+
+def test():
+    test_cases = [((2012, 9, 30, 2012, 10, 30), 30),
+                  ((2012, 1, 1, 2013, 1, 1), 360),
+                  ((2012, 9, 1, 2012, 9, 4), 3)]
+
+    for (args, answer) in test_cases:
+        result = daysBetweenDates(*args)
+        if result != answer:
+            print("Test with data:", args, "failed")
+        else:
+            print("Test case passed!")
+
+
+
+test()
+