Added doctest and more explanation about Dijkstra execution. (#1014)

* Added doctest and more explanation about Dijkstra execution.

* tests were not passing with python2 due to missing __init__.py file at number_theory folder

* Removed the dot at the beginning of the imported modules names because 'python3 -m doctest -v data_structures/hashing/*.py' and 'python3 -m doctest -v data_structures/stacks/*.py' were failing not finding hash_table.py and stack.py modules.

* Moved global code to main scope and added doctest for project euler problems 1 to 14.

* Added test case for negative input.

* Changed N variable to do not use end of line scape because in case there is a space after it the script will break making it much more error prone.

* Added problems description and doctests to the ones that were missing. Limited line length to 79 and executed python black over all scripts.

* Changed the way files are loaded to support pytest call.

* Added __init__.py to problems to make them modules and allow pytest execution.

* Added project_euler folder to test units execution

* Changed 'os.path.split(os.path.realpath(__file__))' to 'os.path.dirname()'

project_euler/problem_05/sol1.py

@@ -1,21 +1,46 @@
-'''
+"""
 Problem:
-2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.
-What is the smallest positive number that is evenly divisible(divisible with no remainder) by all of the numbers from 1 to N?
-'''
+2520 is the smallest number that can be divided by each of the numbers from 1
+to 10 without any remainder.
+
+What is the smallest positive number that is evenly divisible(divisible with no
+remainder) by all of the numbers from 1 to N?
+"""
 from __future__ import print_function
 
-n = int(input())
-i = 0
-while 1:
-    i+=n*(n-1)
-    nfound=0
-    for j in range(2,n):
-        if (i%j != 0):
-            nfound=1
+try:
+    raw_input  # Python 2
+except NameError:
+    raw_input = input  # Python 3
+
+
+def solution(n):
+    """Returns the smallest positive number that is evenly divisible(divisible
+    with no remainder) by all of the numbers from 1 to n.
+    
+    >>> solution(10)
+    2520
+    >>> solution(15)
+    360360
+    >>> solution(20)
+    232792560
+    >>> solution(22)
+    232792560
+    """
+    i = 0
+    while 1:
+        i += n * (n - 1)
+        nfound = 0
+        for j in range(2, n):
+            if i % j != 0:
+                nfound = 1
+                break
+        if nfound == 0:
+            if i == 0:
+                i = 1
+            return i
             break
-    if(nfound==0):
-        if(i==0):
-            i=1
-        print(i)
-        break
+
+
+if __name__ == "__main__":
+    print(solution(int(raw_input().strip())))