Ticket #14512: ticket14512.3.diff

regressiontests/utils/decorators.py

@@ -3 +3 @@
 from django.template import Template, Context
 from django.template.response import TemplateResponse
 from django.test import TestCase, RequestFactory
-from django.utils.decorators import decorator_from_middleware
+from django.utils.decorators import decorator_from_middleware, wraps, view_decorator
+from django.views.generic import View
 
 
 xview_dec = decorator_from_middleware(XViewMiddleware)
@@ -104 +105 @@
         self.assertTrue(getattr(request, 'process_response_reached', False))
         # Check that process_response saw the rendered content
         self.assertEqual(request.process_response_content, "Hello world")
+
+
+def simple_dec(func): 
+    """ 
+    Simple decorator for testing view_decorator. It assumes a request
+    argument and one extra argument. Prepends string "decorator:" to the
+    result.
+    """ 
+    def wrapper(request, arg, func=func): 
+        return "decorator:" + func(request, arg) 
+    wrapper = wraps(func)(wrapper) 
+    wrapper.is_decorated = True 
+    return wrapper 
+
+
+class TextView(View):
+    def __init__(self, *args, **kwargs):
+        super(TextView, self).__init__(*args, **kwargs)
+    def get(self, request, text):
+        return "get1:" + text
+    def post(self, request, text):
+        return "post1:" + text
+TextView = view_decorator(simple_dec)(TextView)
+
+
+class BaseTextView(View):
+    def __init__(self, *args, **kwargs):
+        super(BaseTextView, self).__init__(*args, **kwargs)
+
+    def get(self, request, text):
+        return "get1:" + text
+
+
+class ExtendedTextView(BaseTextView):
+    def __init__(self, **initargs):
+        self.recursion_count = 0
+        super(ExtendedTextView, self).__init__(**initargs)
+
+    def get(self, *args, **kwargs):
+        self.recursion_count += 1
+        if self.recursion_count > 10:
+            raise Exception("Decoration caused recursive super() calls.")
+        return "get2:" + super(ExtendedTextView, self).get(*args, **kwargs)
+ExtendedTextView = view_decorator(simple_dec)(ExtendedTextView)
+
+
+class ClassBasedViewDecorationTests(TestCase): 
+    rf = RequestFactory()
+
+    def test_decorate_view(self):
+        self.assertTrue(getattr(TextView.as_view(), "is_decorated", False),
+                        "Class based view decorator didn't preserve attributes.")
+        self.assertEqual(TextView.as_view()(self.rf.get('/'), "hello"),
+                         "decorator:get1:hello")
+        self.assertEqual(TextView.as_view()(self.rf.post('/'), "hello"),
+                         "decorator:post1:hello")
+
+    def test_decorate_derived_view(self):
+        # NOTE: it's important for this test, that the definition
+        # and decoration of the class happens in the *same scope*.
+        view = ExtendedTextView.as_view()
+        result = view(self.rf.get('/'), "A")
+        self.assertEqual(result, "decorator:get2:get1:A")
+
+    def test_base_unmodified(self):
+        DecoratedView = view_decorator(simple_dec)(BaseTextView)
+
+        # since a super(TestView) is called in the __init__ method of the
+        # following assertion, and the DecorationView instance is no instance of
+        # TestView, a TypeError is raised. This is a Python subtlety, and
+        # therefore not the concern of view_decorator.
+        self.assertRaises(TypeError, DecoratedView.as_view(), (self.rf.get('/'), "A"))
+
+        self.assertEqual(BaseTextView.as_view()(self.rf.get('/'), "A"), "get1:A")
+        self.assertFalse(DecoratedView is BaseTextView)
+        self.assertEqual(DecoratedView.mro(), [DecoratedView] + BaseTextView.mro()[1:])
+