Add pytest for heap_sort

Author: NavanithaSri

tests/test_sorts.py

@@ -0,0 +1,8 @@
+from sorts.heap_sort import heap_sort
+
+def test_heap_sort():
+    assert heap_sort([]) == []
+    assert heap_sort([1]) == [1]
+    assert heap_sort([5,2,5,1]) == [1,2,5,5]
+    assert heap_sort([1,2,3,4]) == [1,2,3,4]
+    assert heap_sort([5,4,3,2,1]) == [1,2,3,4,5]