added abstract factory pattern

pypatterns/creational/factory.py

@@ -3,11 +3,10 @@ from abc import abstractmethod, ABCMeta
 
 class Factory(object, metaclass=ABCMeta):
     """
-    Abstract Factory Class.
+    Factory Interface.
 
     All Factories should inherit this class and overwrite the create method.
     """
-
     @abstractmethod
     def create(self, **kwargs):
         """
@@ -19,3 +18,37 @@ class Factory(object, metaclass=ABCMeta):
         """
         pass
 
+
+class AbstractFactory(object):
+    """
+    Abstract Factory Class.
+    """
+    def __init__(self):
+        """
+        Initialize the abstract factory.
+
+        Concrete implementations should call this from within their own __init__ method
+        and register all their factories to keys using the register method.
+        """
+        self._factories = dict()
+
+    @abstractmethod
+    def create(self, **kwargs):
+        """
+        Abstract create method.
+
+        Concrete implementations should return a new instance of an object by calling the appropriate factory.
+
+        @param kwargs: Arguments for object creation.
+        """
+        pass
+
+    def _register(self, key, factory):
+        """
+        Register a factory to a key.
+
+        @param key: Key for identifying which factory to use.
+        @type key: str
+        @param factory: The factory to register to the key.
+        """
+        self._factories[str(key)] = factory()

tests/creational_tests/test_factory.py

@@ -1,5 +1,5 @@
 from unittest import TestCase
-from pypatterns.creational.factory import Factory
+from pypatterns.creational.factory import Factory, AbstractFactory
 
 
 class FactoryTestCase(TestCase):
@@ -35,18 +35,6 @@ class FactoryTestCase(TestCase):
         self.cat_factory = CatFactory()
         self.dog_factory = DogFactory()
 
-    def test_not_implemented(self):
-        """
-        Test that TypeError is raised when the create method is not overridden.
-
-        @raise AssertionError: If the test fails.
-        """
-        with self.assertRaises(TypeError):
-            class EmptyFactory(Factory):
-                pass
-
-            EmptyFactory()
-
     def test_create(self):
         """
         Test the create method.
@@ -61,3 +49,58 @@ class FactoryTestCase(TestCase):
 
         self.assertEquals('Meow', cat.speak())
         self.assertEquals('Woof', dog.speak())
+
+
+class AbstractFactoryTestCase(TestCase):
+    """
+    Unit testing class for the AbstractFactory class.
+    """
+    def setUp(self):
+        """
+        Initialize testing data.
+        """
+        class Cat(object):
+            def speak(self):
+                return 'Meow'
+
+        class Dog(object):
+            def speak(self):
+                return 'Woof'
+
+        class CatFactory(Factory):
+            def create(self, **kwargs):
+                return Cat()
+
+        class DogFactory(Factory):
+            def create(self, **kwargs):
+                return Dog()
+
+        class AnimalFactory(AbstractFactory):
+
+            def __init__(self):
+                super().__init__()
+                self._register('cat', CatFactory)
+                self._register('dog', DogFactory)
+
+            def create(self, animal_type):
+                return self._factories[animal_type].create()
+
+        self.cat_class = Cat
+        self.dog_class = Dog
+        self.animal_factory = AnimalFactory()
+
+    def test_create(self):
+        """
+        Test the create method.
+
+        @raise AssertionError: If the test fails.
+        """
+        cat = self.animal_factory.create('cat')
+        dog = self.animal_factory.create('dog')
+
+        self.assertEquals(self.cat_class, cat.__class__)
+        self.assertEquals(self.dog_class, dog.__class__)
+
+        self.assertEquals('Meow', cat.speak())
+        self.assertEquals('Woof', dog.speak())
+