diff --git a/flask/app.py b/flask/app.py
index dbb64646..2ca641e3 100644
--- a/flask/app.py
+++ b/flask/app.py
@@ -863,6 +863,15 @@ class Flask(_PackageBoundObject):
         function accepts the same arguments).
         """
         from werkzeug import create_environ
+        environ_overrides = kwargs.setdefault('environ_overrides', {})
+        if self.config.get('SERVER_NAME'):
+            server_name = self.config.get('SERVER_NAME')
+            if ':' not in server_name:
+                server_name += ':80'
+            http_host, http_port = server_name.split(':')
+            environ_overrides.setdefault('SERVER_NAME', server_name)
+            environ_overrides.setdefault('HTTP_HOST', server_name)
+            environ_overrides.setdefault('SERVER_PORT', http_port)
         return self.request_context(create_environ(*args, **kwargs))
 
     def wsgi_app(self, environ, start_response):
diff --git a/tests/flask_tests.py b/tests/flask_tests.py
index 8eecafc0..eac3efca 100644
--- a/tests/flask_tests.py
+++ b/tests/flask_tests.py
@@ -501,6 +501,23 @@ class BasicFunctionalityTestCase(unittest.TestCase):
         self.assertEqual(repr(flask.g), '<LocalProxy unbound>')
         self.assertFalse(flask.g)
 
+    def test_proper_test_request_context(self):
+        app = flask.Flask(__name__)
+        app.config.update(
+            SERVER_NAME='localhost.localdomain:5000'
+        )
+        @app.route('/')
+        def index():
+            return None
+
+        with app.test_request_context('/'):
+            assert flask.url_for('index', _external=True) == 'http://localhost.localdomain:5000/'
+
+        def testit():
+            with app.test_request_context('/', environ_overrides={'HTTP_HOST': 'localhost'}):
+                pass
+        self.assertRaises(ValueError, testit)
+
 
 class JSONTestCase(unittest.TestCase):