add: test for calls of concrete implementations

Author: fkromer

test_bridge.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+from bridge import DrawingAPI1, DrawingAPI2, CircleShape
+from sys import version_info
+
+if version_info < (2, 7):
+    import unittest2 as unittest
+else:
+    import unittest
+
+from unittest.mock import patch
+
+class BridgeTest(unittest.TestCase):
+
+    def test_bridge_shall_draw_with_concrete_implementation(cls):
+        ci1 = DrawingAPI1()
+        ci2 = DrawingAPI2()
+        with patch.object(ci1, 'draw_circle') as mock_ci1_draw_circle,\
+             patch.object(ci2, 'draw_circle') as mock_ci2_draw_circle:
+            sh1 = CircleShape(1, 2, 3, ci1)
+            sh1.draw()
+            cls.assertEqual(mock_ci1_draw_circle.call_count, 1)
+            sh2 = CircleShape(1, 2, 3, ci2)
+            sh2.draw()
+            cls.assertEqual(mock_ci2_draw_circle.call_count, 1)
+
+if __name__ == "__main__":
+    unittest.main()
+