added dummy class and began writing unit tests

tests/creational_tests/test_singleton.py

@@ -0,0 +1,14 @@
+from unittest import TestCase
+from creational import singleton
+
+
+class SingletonTestCase(TestCase):
+    """
+    Unit testing class for the singleton design pattern.
+    """
+    def setUp(self):
+        """
+        Initialize testing data.
+
+        :return:
+        """