Add a test for filtered params.

oauthlib/oauth.py

@@ -20,6 +20,7 @@
 SIGNATURE_TYPE_AUTH_HEADER = u'AUTH_HEADER'
 SIGNATURE_TYPE_QUERY = u'QUERY'
 
+
 class OAuthClient(object):
     """An OAuth client used to sign OAuth requests"""
     def __init__(self, client_key, client_secret,

tests/test_utils.py

@@ -0,0 +1,34 @@
+from __future__ import absolute_import
+
+from .unittest import TestCase
+
+from oauthlib.utils import *
+
+
+class UtilsTests(TestCase):
+
+    def test_filter_params(self):
+
+        @filter_params
+        def special_test_function(params, realm=None):
+            """ I am a special test function """
+            return 'OAuth ' + ','.join(['='.join([k, v]) for k, v in params])
+
+        # check that the docstring got through
+        self.assertEqual(special_test_function.__doc__, " I am a special test function ")
+
+        sample_params = [
+                ("notoauth", "shouldnotbehere"),
+                ("oauth_consumer_key", "9djdj82h48djs9d2"),
+                ("oauth_token", "kkk9d7dh3k39sjv7"),
+                ("notoautheither", "shouldnotbehere")
+            ]
+
+        # Check that the filtering works as per design.
+        #   Any param that does not start with 'oauth'
+        #   should not be present in the filtered params
+        filtered_params = special_test_function(sample_params)
+        self.assertFalse("notoauth" in filtered_params)
+        self.assertTrue("oauth_consumer_key" in filtered_params)
+        self.assertTrue("oauth_token" in filtered_params)
+        self.assertFalse("notoautheither" in filtered_params)