--- a/testing/web-platform/tests/webdriver/tests/navigation/current_url.py
+++ b/testing/web-platform/tests/webdriver/tests/navigation/current_url.py
@@ -74,17 +74,17 @@ def test_set_malformed_url(session):
                                     {"url": "foo"})
 
     assert_error(result, "invalid argument")
 
 def test_get_current_url_after_modified_location(session):
     start = session.transport.send("GET", "session/%s/url" % session.session_id)
     session.execute_script("window.location.href = 'about:blank#wd_test_modification'")
     wait(session,
-         lambda s: s.transport.send("GET", "session/%s/url" % session.session_id) != start.body["value"],
+         lambda s: s.transport.send("GET", "session/%s/url" % s.session_id) != start.body["value"],
          "URL did not change")
     result = session.transport.send("GET", "session/%s/url" % session.session_id)
 
     assert_success(result, "about:blank#wd_test_modification")
 
 def test_get_current_url_nested_browsing_context(session, create_frame):
     session.url = "about:blank#wd_from_within_frame"
     session.switch_frame(create_frame())