spiral matrix and prime factors exercise

python/prime-factors/.exercism/metadata.json

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+{"track":"python","exercise":"prime-factors","id":"8594f50d455a42c2bcaaf99a23da57ec","url":"https://exercism.io/my/solutions/8594f50d455a42c2bcaaf99a23da57ec","handle":"Xevion","is_requester":true,"auto_approve":false}

python/prime-factors/README.md

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+# Prime Factors
+
+Compute the prime factors of a given natural number.
+
+A prime number is only evenly divisible by itself and 1.
+
+Note that 1 is not a prime number.
+
+## Example
+
+What are the prime factors of 60?
+
+- Our first divisor is 2. 2 goes into 60, leaving 30.
+- 2 goes into 30, leaving 15.
+  - 2 doesn't go cleanly into 15. So let's move on to our next divisor, 3.
+- 3 goes cleanly into 15, leaving 5.
+  - 3 does not go cleanly into 5. The next possible factor is 4.
+  - 4 does not go cleanly into 5. The next possible factor is 5.
+- 5 does go cleanly into 5.
+- We're left only with 1, so now, we're done.
+
+Our successful divisors in that computation represent the list of prime
+factors of 60: 2, 2, 3, and 5.
+
+You can check this yourself:
+
+- 2 * 2 * 3 * 5
+- = 4 * 15
+- = 60
+- Success!
+
+## 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 the appropriate command below ([why they are different](https://github.com/pytest-dev/pytest/issues/1629#issue-161422224)):
+
+- Python 2.7: `py.test prime_factors_test.py`
+- Python 3.4+: `pytest prime_factors_test.py`
+
+Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version):
+`python -m pytest prime_factors_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/prime-factors` 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
+
+The Prime Factors Kata by Uncle Bob [http://butunclebob.com/ArticleS.UncleBob.ThePrimeFactorsKata](http://butunclebob.com/ArticleS.UncleBob.ThePrimeFactorsKata)
+
+## Submitting Incomplete Solutions
+
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

python/prime-factors/prime_factors.py

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+def factors(value):
+    factors, n = [], 2
+    while value > 1:
+        while value % n == 0:
+            factors.append(n)
+            value /= n
+        n += 1
+    return factors

python/prime-factors/prime_factors_test.py

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+import unittest
+
+from prime_factors import factors
+
+
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.1.0
+
+class PrimeFactorsTest(unittest.TestCase):
+    def test_no_factors(self):
+        self.assertEqual(factors(1), [])
+
+    def test_prime_number(self):
+        self.assertEqual(factors(2), [2])
+
+    def test_square_of_a_prime(self):
+        self.assertEqual(factors(9), [3, 3])
+
+    def test_cube_of_a_prime(self):
+        self.assertEqual(factors(8), [2, 2, 2])
+
+    def test_product_of_primes_and_non_primes(self):
+        self.assertEqual(factors(12), [2, 2, 3])
+
+    def test_product_of_primes(self):
+        self.assertEqual(factors(901255), [5, 17, 23, 461])
+
+    def test_factors_include_a_large_prime(self):
+        self.assertEqual(factors(93819012551), [11, 9539, 894119])
+
+
+if __name__ == '__main__':
+    unittest.main()