started work on decorator pattern.

pypatterns/structural/decorator.py

@@ -0,0 +1,31 @@
+from functools import partial
+from abc import ABCMeta, abstractmethod
+
+
+class Decorator(object, metaclass=ABCMeta):
+
+    def __get__(self, instance, owner):
+        return partial(self.__call__, instance)
+
+    @abstractmethod
+    def __call__(self, *args, **kwargs):
+        pass
+
+
+class DecoratorSimple(Decorator, metaclass=ABCMeta):
+
+    def __init__(self, func):
+        self.func = func
+
+
+class DecoratorArgs(Decorator, metaclass=ABCMeta):
+
+    @abstractmethod
+    def __init__(self, *args, **kwargs):
+        pass
+
+
+class Wrap(DecoratorSimple):
+
+    def __call__(self, instance, func, *args, **kwargs):
+        return lambda: self.func(instance, func, *args, **kwargs)

tests/structural_tests/test_decorator.py

@@ -0,0 +1,103 @@
+import time
+from unittest import TestCase
+from pypatterns.structural.decorator import DecoratorSimple, DecoratorArgs, Wrap
+
+
+class DecoratorSimpleTestCase(TestCase):
+    """
+    Unit testing class for the DecoratorSimple class.
+    """
+    def setUp(self):
+        """
+        Initialize testing data.
+        """
+        class TimeThis(DecoratorSimple):
+
+            def __call__(self, *args, **kwargs):
+                start = time.time()
+                result = self.func(*args, **kwargs)
+                end = time.time() - start
+                self.end = end
+                return result
+
+        self.time_this = TimeThis
+
+    def test_decorate_function(self):
+        """
+        Test decorating a function.
+
+        @raise AssertionError: If the test fails.
+        """
+        @self.time_this
+        def slow_function():
+            time.sleep(1)
+            return 'foo'
+
+        self.assertEquals('foo', slow_function())
+        self.assertAlmostEqual(1.0, slow_function.end, delta=1.0)
+
+    def test_decorate_function_with_args(self):
+        """
+        Test decoration a function with arguments.
+
+        @raise AssertionError: If the test fails.
+        """
+        @self.time_this
+        def slow_function(n):
+            time.sleep(n)
+            return 'foo'
+
+        self.assertEquals('foo', slow_function(2))
+        self.assertAlmostEqual(2.0, slow_function.end, delta=1.0)
+
+
+class DecoratorArgsTestCase(TestCase):
+    """
+    Unit testing class for the DecoratorArgs class.
+    """
+    def setUp(self):
+        """
+        Initialize testing data.
+        """
+        class Alert(DecoratorArgs):
+
+            def __init__(self, alert_time):
+                self.alert_time = alert_time
+
+            @Wrap
+            def __call__(self, func, *args, **kwargs):
+                start = time.time()
+                return_val = func(*args, **kwargs)
+                end = time.time() - start
+                if end > self.alert_time:
+                    return return_val, True
+                return return_val, False
+
+        self.alert = Alert
+
+    def test_decorate(self):
+        """
+        Test decorating a function.
+
+        @raise AssertionError: If the test fails.
+        """
+        @self.alert(1)
+        def slow_function():
+            time.sleep(2)
+            return 'foo'
+
+        self.assertEquals(('foo', True), slow_function())
+
+    def test_decorate_args(self):
+        """
+        Test decorating a function with args.
+
+        @raise AssertionError: If the test fails.
+        """
+
+        @self.alert(1)
+        def slow_function(n):
+            time.sleep(n)
+            return 'foo'
+
+        self.assertEquals(('foo', True), slow_function(2))