diff --git a/lms/djangoapps/lti_provider/tests/test_signature_validator.py b/lms/djangoapps/lti_provider/tests/test_signature_validator.py
index 367f415b49..2b746846f6 100644
--- a/lms/djangoapps/lti_provider/tests/test_signature_validator.py
+++ b/lms/djangoapps/lti_provider/tests/test_signature_validator.py
@@ -111,10 +111,10 @@ class SignatureValidatorTest(TestCase):
         Verify that the signature validaton library method is called using the
         correct parameters derived from the HttpRequest.
         """
-        body = 'oauth_signature_method=HMAC-SHA1&oauth_version=1.0'
+        body = u'oauth_signature_method=HMAC-SHA1&oauth_version=1.0'
         content_type = 'application/x-www-form-urlencoded'
         request = RequestFactory().post('/url', body, content_type=content_type)
         headers = {'Content-Type': content_type}
         SignatureValidator(self.lti_consumer).verify(request)
         verify_mock.assert_called_once_with(
-            request.build_absolute_uri(), 'POST', body, headers)
+            request.build_absolute_uri(), 'POST', body.encode('utf-8'), headers)