Merge pull request YearOfProgramming#361 from sarcodian/python_7 revi…

…ewed by ningyuansg

[Python] Challenge 7 (reviewed and merged)

challenge_7/python/sarcodian/READ.me

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+Assume we are giving a list of unorder consective ints. We have to find
+which int is missing. Since we know a single int is missing, we know
+that the original list must have a length of given list + 1. 
+Therefore, we sum all elements of range( lenght_of_given_list + 1) and 
+subtract the sum of all elements in the given list.

challenge_7/python/sarcodian/src/challenge_7.py

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+def missing_int(L):
+    '''
+    Ask for a list and return the missing value
+    '''
+
+    sum_n = 0
+    sum_n_less_1 = 0
+
+    for i in range(len(L)+1):
+        sum_n += i
+
+    sum_n_less_1 = sum(L)
+
+    return sum_n - sum_n_less_1
+
+

challenge_7/python/sarcodian/src/challenge_7_tests.py

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+# we start by importing the unittest module
+import unittest
+
+# Next lets import our function that we intend to do testing on
+#
+# **We could also import all functions by using * or just import the module
+# itself but for now lets just import the function
+from challenge_7 import missing_int
+
+# lets define our suite of tests as a class and lets inherit from unittest.TestCase
+class TestBinaryMethods(unittest.TestCase):
+
+    def test_missingInt(self):
+
+        self.assertEqual(missing_int([1,3,4,0]), 2)
+        self.assertEqual(missing_int([1,2,3]), 0)
+        self.assertEqual(missing_int([0,1,2,4]), 3)
+
+# if the python file is ran by itself run unittest
+# This allows us to import the members of the file without running main if we need to
+if __name__ == '__main__':
+    unittest.main()