Implemented bridge design pattern.

pypatterns/structural/bridge.py

@@ -0,0 +1,15 @@
+from abc import ABCMeta
+
+
+class Bridge(object, metaclass=ABCMeta):
+    """
+    Base Bridge class as part of the Bridge design pattern.
+    """
+    def __init__(self, implementor):
+        """
+        Initialize a new Bridge instance.
+
+        @param implementor: The implementor that concrete classes should call upon to do some action.
+        """
+        self.implementor = implementor
+

tests/structural_tests/test_bridge.py

@@ -0,0 +1,93 @@
+from unittest import TestCase
+from pypatterns.structural.bridge import Bridge
+
+
+class BridgeTestCase(TestCase):
+    """
+    Unit testing class for the Bridge class.
+    """
+    def setUp(self):
+        """
+        Initialize testing data.
+        """
+        class DrawingAPI(object):
+
+            def __init__(self): pass
+
+            def draw_circle(self): pass
+
+            def draw_rectangle(self): pass
+
+        class DrawingAPI1(DrawingAPI):
+
+            def draw_circle(self):
+                return 'draw circle 1'
+
+            def draw_rectangle(self):
+                return 'draw rectangle 1'
+
+        class DrawingAPI2(DrawingAPI):
+
+            def draw_circle(self):
+                return 'draw circle 2'
+
+            def draw_rectangle(self):
+                return 'draw rectangle 2'
+
+        class Shape(Bridge):
+
+            def draw(self): pass
+
+            def do_something_high_level(self): pass
+
+        class CircleShape(Shape):
+
+            def draw(self):
+                return self.implementor.draw_circle()
+
+            def do_something_high_level(self):
+                return 'high level circle'
+
+        class RectangleShape(Shape):
+
+            def draw(self):
+                return self.implementor.draw_rectangle()
+
+            def do_something_high_level(self):
+                return 'high level rectangle'
+
+        self.drawing_api_one = DrawingAPI1()
+        self.drawing_api_two = DrawingAPI2()
+
+        self.circle_shape_one = CircleShape(self.drawing_api_one)
+        self.circle_shape_two = CircleShape(self.drawing_api_two)
+
+        self.rectangle_shape_one = RectangleShape(self.drawing_api_one)
+        self.rectangle_shape_two = RectangleShape(self.drawing_api_two)
+
+    def test_init(self):
+        """
+        Test the __init__ method.
+
+        @raise AssertionError: If the test fails.
+        """
+        self.assertEquals(self.drawing_api_one, self.circle_shape_one.implementor)
+        self.assertEquals(self.drawing_api_two, self.circle_shape_two.implementor)
+        self.assertEquals(self.drawing_api_one, self.rectangle_shape_one.implementor)
+        self.assertEquals(self.drawing_api_two, self.rectangle_shape_two.implementor)
+
+    def test_implementation(self):
+        """
+        Test an implementation of the bridge pattern
+
+        @raise AssertionError: If the test fails.
+        """
+        self.assertEquals('draw circle 1', self.circle_shape_one.draw())
+        self.assertEquals('draw circle 2', self.circle_shape_two.draw())
+        self.assertEquals('draw rectangle 1', self.rectangle_shape_one.draw())
+        self.assertEquals('draw rectangle 2', self.rectangle_shape_two.draw())
+
+        self.assertEquals('high level circle', self.circle_shape_one.do_something_high_level())
+        self.assertEquals('high level circle', self.circle_shape_two.do_something_high_level())
+        self.assertEquals('high level rectangle', self.rectangle_shape_one.do_something_high_level())
+        self.assertEquals('high level rectangle', self.rectangle_shape_two.do_something_high_level())