diff --git a/tests/wpt/meta/MANIFEST.json b/tests/wpt/meta/MANIFEST.json
index 045d0b4f0d609..88418a19c8634 100644
--- a/tests/wpt/meta/MANIFEST.json
+++ b/tests/wpt/meta/MANIFEST.json
@@ -465041,7 +465041,7 @@
         []
        ],
        "executorservo.py": [
-        "0d22471e90e83fbfd80010001e8c60f509af8902",
+        "3250c74ff4397d229e370a8c317b0e2a269dc9a8",
         []
        ],
        "executorservodriver.py": [
diff --git a/tests/wpt/tests/tools/wptrunner/wptrunner/executors/executorservo.py b/tests/wpt/tests/tools/wptrunner/wptrunner/executors/executorservo.py
index 0d22471e90e83..3250c74ff4397 100644
--- a/tests/wpt/tests/tools/wptrunner/wptrunner/executors/executorservo.py
+++ b/tests/wpt/tests/tools/wptrunner/wptrunner/executors/executorservo.py
@@ -276,7 +276,7 @@ def do_test(self, test):
 
         return self.convert_result(test, result)
 
-    def on_output(line):
+    def on_output(self, line):
         line = line.decode("utf8", "replace")
         if self.interactive:
             print(line)
@@ -345,12 +345,12 @@ def do_crashtest(self, protocol, url, timeout):
         env["RUST_BACKTRACE"] = "1"
 
         self.command = build_servo_command(self.test,
-                                      self.test_url,
-                                      self.browser,
-                                      self.binary,
-                                      False,
-                                      self.debug_info,
-                                      extra_args=["-x"])
+                                           self.test_url,
+                                           self.browser,
+                                           self.binary,
+                                           False,
+                                           self.debug_info,
+                                           extra_args=["-x"])
 
         if not self.interactive:
             self.proc = ProcessHandler(self.command,