Fixed #5897 -- Added the Content-Length response header in CommonMiddleware

Thanks Tim Graham for the review.

3 files changed, 31 insertions, 5 deletions

diff --git a/tests/middleware/tests.py b/tests/middleware/tests.py
index f87bb9d71c..f9ef951b44 100644
--- a/tests/middleware/tests.py
+++ b/tests/middleware/tests.py
@@ -285,6 +285,27 @@ class CommonMiddlewareTest(SimpleTestCase):
         second_res = CommonMiddleware().process_response(second_req, HttpResponse('content'))
         self.assertEqual(second_res.status_code, 304)
 
+    # Tests for the Content-Length header
+
+    def test_content_length_header_added(self):
+        response = HttpResponse('content')
+        self.assertNotIn('Content-Length', response)
+        response = CommonMiddleware().process_response(HttpRequest(), response)
+        self.assertEqual(int(response['Content-Length']), len(response.content))
+
+    def test_content_length_header_not_added_for_streaming_response(self):
+        response = StreamingHttpResponse('content')
+        self.assertNotIn('Content-Length', response)
+        response = CommonMiddleware().process_response(HttpRequest(), response)
+        self.assertNotIn('Content-Length', response)
+
+    def test_content_length_header_not_changed(self):
+        response = HttpResponse()
+        bad_content_length = len(response.content) + 10
+        response['Content-Length'] = bad_content_length
+        response = CommonMiddleware().process_response(HttpRequest(), response)
+        self.assertEqual(int(response['Content-Length']), bad_content_length)
+
     # Other tests
 
     @override_settings(DISALLOWED_USER_AGENTS=[re.compile(r'foo')])
@@ -445,6 +466,9 @@ class ConditionalGetMiddlewareTest(SimpleTestCase):
 
     def test_content_length_header_added(self):
         content_length = len(self.resp.content)
+        # Already set by CommonMiddleware, remove it to check that
+        # ConditionalGetMiddleware readds it.
+        del self.resp['Content-Length']
         self.assertNotIn('Content-Length', self.resp)
         self.resp = ConditionalGetMiddleware().process_response(self.req, self.resp)
         self.assertIn('Content-Length', self.resp)
diff --git a/tests/project_template/test_settings.py b/tests/project_template/test_settings.py
index d153c4d95f..a0047dd836 100644
--- a/tests/project_template/test_settings.py
+++ b/tests/project_template/test_settings.py
@@ -41,6 +41,7 @@ class TestStartProjectSettings(TestCase):
             response = self.client.get('/empty/')
             headers = sorted(response.serialize_headers().split(b'\r\n'))
             self.assertEqual(headers, [
+                b'Content-Length: 0',
                 b'Content-Type: text/html; charset=utf-8',
                 b'X-Frame-Options: SAMEORIGIN',
             ])
diff --git a/tests/wsgi/tests.py b/tests/wsgi/tests.py
index f472d4fab9..03ac7ee706 100644
--- a/tests/wsgi/tests.py
+++ b/tests/wsgi/tests.py
@@ -41,11 +41,12 @@ class WSGITest(SimpleTestCase):
 
         self.assertEqual(response_data["status"], "200 OK")
         self.assertEqual(
-            response_data["headers"],
-            [('Content-Type', 'text/html; charset=utf-8')])
-        self.assertEqual(
-            bytes(response),
-            b"Content-Type: text/html; charset=utf-8\r\n\r\nHello World!")
+            set(response_data["headers"]),
+            {('Content-Length', '12'), ('Content-Type', 'text/html; charset=utf-8')})
+        self.assertTrue(bytes(response) in [
+            b"Content-Length: 12\r\nContent-Type: text/html; charset=utf-8\r\n\r\nHello World!",
+            b"Content-Type: text/html; charset=utf-8\r\nContent-Length: 12\r\n\r\nHello World!"
+        ])
 
     def test_file_wrapper(self):
         """