implemented prototype pattern

pypatterns/creational/prototype.py

@@ -0,0 +1,26 @@
+from copy import deepcopy
+from types import MethodType
+
+
+class Prototype(object):
+    """
+    Prototype design pattern abstract class.
+    """
+    def copy(self, **attributes):
+        """
+        Copy this object and optionally update attributes.
+
+        @param attributes: Keyword arguments of any attributes you wish to update.
+        @return: A copy of this object with the updated attributes.
+        """
+        obj = deepcopy(self)
+        for attribute in attributes:
+            if callable(attributes[attribute]):
+                setattr(obj, attribute, MethodType(attributes[attribute], obj))
+            else:
+                setattr(obj, attribute, attributes[attribute])
+
+        return obj
+
+
+

tests/creational_tests/test_prototype.py

@@ -0,0 +1,103 @@
+from math import sqrt
+from unittest import TestCase
+from pypatterns.creational.prototype import Prototype
+
+
+class PrototypeTestCase(TestCase):
+    """
+    Unit testing class for the Prototype class.
+    """
+    def setUp(self):
+        """
+        Initialize testing data.
+        """
+        class Point(Prototype):
+
+            def __init__(self, x, y):
+                self.x = x
+                self.y = y
+
+            def move(self, x, y):
+                self.x += x
+                self.y += y
+
+        self.__point_class = Point
+        self.maxDiff = None
+
+    def test_copy_instances(self):
+        """
+        Test that copy returns a new instance.
+
+        @raise AssertionError: If the test fails.
+        """
+        point_one = self.__point_class(5, 5)
+        point_two = point_one.copy()
+
+        self.assertEquals(point_one.__class__, point_two.__class__)
+        self.assertNotEquals(id(point_one), id(point_two))
+
+    def test_identical_copy(self):
+        """
+        Test the copy method without updating any attributes.
+
+        @raise AssertionError: If the test fails.
+        """
+        point_one = self.__point_class(5, 5)
+        point_two = point_one.copy()
+
+        self.assertEquals(point_one.__dict__, point_two.__dict__)
+
+    def test_update_attributes_copy(self):
+        """
+        Test the copy method with updated attributes.
+
+        @raise AssertionError: If the test fails.
+        """
+        point_one = self.__point_class(10, 10)
+        point_two = point_one.copy(x=15, y=20)
+        point_three = point_two.copy()
+
+        self.assertEquals(point_one.__dict__, {'x': 10, 'y': 10})
+        self.assertEquals(point_two.__dict__, {'x': 15, 'y': 20})
+        self.assertEquals(point_three.__dict__, point_two.__dict__)
+
+    def test_add_attributes_copy(self):
+        """
+        Test the copy method with completely new attributes.
+
+        @raise AssertionError: If the test fails.
+        """
+        point_one = self.__point_class(15, 15)
+        point_two = point_one.copy(z=20)
+        point_three = point_two.copy()
+
+        self.assertEquals(point_one.x, point_two.x)
+        self.assertEquals(point_one.y, point_two.y)
+        self.assertFalse(hasattr(point_one, 'z'))
+        self.assertTrue(hasattr(point_two, 'z'))
+        self.assertEquals(point_two.z, 20)
+        self.assertEquals(point_three.__dict__, point_two.__dict__)
+
+    def test_add_function_copy(self):
+        """
+        Test the copy method with a new instance method.
+
+        @raise AssertionError: If the test fails.
+        """
+        point_one = self.__point_class(20, 25)
+
+        def distance_to(this, other):
+            return sqrt((this.x - other.x)**2 + (this.y - other.y)**2)
+
+        point_two = point_one.copy(distance_to=distance_to)
+        point_three = point_two.copy()
+
+        self.assertFalse(hasattr(point_one, 'distance_to'))
+        self.assertTrue(hasattr(point_two, 'distance_to'))
+        self.assertEquals(point_two.distance_to(point_one), 0)
+        self.assertTrue(hasattr(point_three, 'distance_to'))
+        self.assertEquals(point_three.distance_to(point_two), 0)
+
+
+
+