Python: leap

python/leap/.exercism/metadata.json

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+{"track":"python","exercise":"leap","id":"3941a91613fc47449adec3c2db33f5fa","url":"https://exercism.io/my/solutions/3941a91613fc47449adec3c2db33f5fa","handle":"DmitryKokorin","is_requester":true,"auto_approve":false}

python/leap/README.md

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+# Leap
+
+Given a year, report if it is a leap year.
+
+The tricky thing here is that a leap year in the Gregorian calendar occurs:
+
+```text
+on every year that is evenly divisible by 4
+  except every year that is evenly divisible by 100
+    unless the year is also evenly divisible by 400
+```
+
+For example, 1997 is not a leap year, but 1996 is.  1900 is not a leap
+year, but 2000 is.
+
+## Notes
+
+Though our exercise adopts some very simple rules, there is more to
+learn!
+
+For a delightful, four minute explanation of the whole leap year
+phenomenon, go watch [this youtube video][video].
+
+[video]: http://www.youtube.com/watch?v=xX96xng7sAE
+
+
+## Exception messages
+
+Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to
+indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not
+every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include
+a message.
+
+To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
+`raise Exception`, you should write:
+
+```python
+raise Exception("Meaningful message indicating the source of the error")
+```
+
+## Running the tests
+
+To run the tests, run `pytest leap_test.py`
+
+Alternatively, you can tell Python to run the pytest module:
+`python -m pytest leap_test.py`
+
+### Common `pytest` options
+
+- `-v` : enable verbose output
+- `-x` : stop running tests on first failure
+- `--ff` : run failures from previous test before running other test cases
+
+For other options, see `python -m pytest -h`
+
+## Submitting Exercises
+
+Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/leap` directory.
+
+You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`.
+
+For more detailed information about running tests, code style and linting,
+please see [Running the Tests](http://exercism.io/tracks/python/tests).
+
+## Source
+
+JavaRanch Cattle Drive, exercise 3 [http://www.javaranch.com/leap.jsp](http://www.javaranch.com/leap.jsp)
+
+## Submitting Incomplete Solutions
+
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

python/leap/leap.py

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+def leap_year(year):
+    return (0 == year % 4 and 0 != year % 100 ) or (0 == year % 400)

python/leap/leap_test.py

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+import unittest
+
+from leap import leap_year
+
+# Tests adapted from `problem-specifications//canonical-data.json`
+
+
+class LeapTest(unittest.TestCase):
+    def test_year_not_divisible_by_4_in_common_year(self):
+        self.assertIs(leap_year(2015), False)
+
+    def test_year_divisible_by_2_not_divisible_by_4_in_common_year(self):
+        self.assertIs(leap_year(1970), False)
+
+    def test_year_divisible_by_4_not_divisible_by_100_in_leap_year(self):
+        self.assertIs(leap_year(1996), True)
+
+    def test_year_divisible_by_4_and_5_is_still_a_leap_year(self):
+        self.assertIs(leap_year(1960), True)
+
+    def test_year_divisible_by_100_not_divisible_by_400_in_common_year(self):
+        self.assertIs(leap_year(2100), False)
+
+    def test_year_divisible_by_100_but_not_by_3_is_still_not_a_leap_year(self):
+        self.assertIs(leap_year(1900), False)
+
+    def test_year_divisible_by_400_in_leap_year(self):
+        self.assertIs(leap_year(2000), True)
+
+    def test_year_divisible_by_400_but_not_by_125_is_still_a_leap_year(self):
+        self.assertIs(leap_year(2400), True)
+
+    def test_year_divisible_by_200_not_divisible_by_400_in_common_year(self):
+        self.assertIs(leap_year(1800), False)
+
+
+if __name__ == "__main__":
+    unittest.main()