add unit tests for an application with default_host

tornado/test/web_test.py

@@ -1364,6 +1364,38 @@ def test_host_matching(self):
         self.assertEqual(response.body, b"[2]")
 
 
+@wsgi_safe
+class DefaultHostMatchingTest(WebTestCase):
+    def get_handlers(self):
+        return []
+
+    def get_app_kwargs(self):
+        return {'default_host': "www.example.com"}
+
+    def test_default_host_matching(self):
+        self.app.add_handlers("www.example.com",
+                              [("/foo", HostMatchingTest.Handler, {"reply": "[0]"})])
+        self.app.add_handlers(r"www\.example\.com",
+                              [("/bar", HostMatchingTest.Handler, {"reply": "[1]"})])
+        self.app.add_handlers("www.test.com",
+                              [("/baz", HostMatchingTest.Handler, {"reply": "[2]"})])
+
+        response = self.fetch("/foo")
+        self.assertEqual(response.body, b"[0]")
+        response = self.fetch("/bar")
+        self.assertEqual(response.body, b"[1]")
+        response = self.fetch("/baz")
+        self.assertEqual(response.code, 404)
+
+        response = self.fetch("/foo", follow_redirects=False, headers={"X-Real-Ip": "127.0.0.1"})
+        self.assertEqual(response.code, 301)
+
+        self.app.default_host = "www.test.com"
+
+        response = self.fetch("/baz")
+        self.assertEqual(response.body, b"[2]")
+
+
 @wsgi_safe
 class NamedURLSpecGroupsTest(WebTestCase):
     def get_handlers(self):

tornado/web.py

@@ -1769,6 +1769,9 @@ class Application(httputil.HTTPServerConnectionDelegate):
             (r"/article/([0-9]+)", ArticleHandler),
         ])
 
+    If there's no match for the current request's host, then ``default_host``
+    parameter value is matched against host regular expressions.
+
     You can serve static files by sending the ``static_path`` setting
     as a keyword argument. We will serve those files from the
     ``/static/`` URI (this is configurable with the