Merge pull request larissalages#157 from sel3ne/master

fixed heapSort and implented unitest

Author: larissalages

classical_algorithms/python/Heap Sort.py renamed to classical_algorithms/python/heapsort.py

@@ -23,18 +23,30 @@ def heapify(arr, n, i):
 def heapSort(arr): 
 	n = len(arr) 
 
+	# empty list returns sorted empty list
+	if n == 0:
+		return []
+
+	# list of size one, returns same list
+	if n == 1:
+		return arr
+
 	# Build a maxheap. 
 	for i in range(n//2 - 1, -1, -1): 
 		heapify(arr, n, i) 
 
 	# One by one extract elements 
 	for i in range(n-1, 0, -1): 
 		arr[i], arr[0] = arr[0], arr[i] # swap 
-		heapify(arr, i, 0) 
-
-print('Enter a list of numbers')
-arr = list(map(int,input().split()))
-heapSort(arr) 
-print('After performing heap sort')
-for i in arr:
-    print(i,end =' ')
+		heapify(arr, i, 0)
+	return arr
+
+
+# not execute the code when imported
+if __name__ == "__main__":
+	print('Enter a list of numbers')
+	arr = list(map(int,input().split()))
+	heapSort(arr) 
+	print('After performing heap sort')
+	for i in arr:
+	    print(i,end =' ')

classical_algorithms/python/tests/test_heap_sort.py

@@ -0,0 +1,26 @@
+import unittest
+from classical_algorithms.python.heapsort import heapSort
+
+class TestHeapSort(unittest.TestCase):
+  def test_heap_sort(self):
+
+    print('None Input')
+    self.assertRaises(TypeError, heapSort, None)
+
+    print('Empty Input')
+    self.assertEqual(heapSort([]), [])
+
+    print('One Element')
+    self.assertEqual(heapSort([13]), [13])
+
+    print('Multipe nElements')
+    test_array = [-23,-1,0,1,10,-10,1000, 2]
+    solution_array = [-23,-10,-1,0,1,2,10,1000]
+
+    self.assertEqual(heapSort(test_array), solution_array)
+
+    print('Successful test_heap_sort\n')
+
+
+if __name__=='__main__':
+  unittest.main()