Add a test that wptrunner fails when it should.

python/servo/testing_commands.py

@@ -200,6 +200,17 @@ class MachCommands(CommandBase):
     def test_tidy(self):
         return tidy.scan()
 
+    @Command('test-wpt-failure',
+             description='Run the web platform tests',
+             category='testing')
+    def test_wpt_failure(self):
+        return not subprocess.call([
+            "bash",
+            path.join("tests", "wpt", "run.sh"),
+            "--include",
+            "infrastructure/failing-test.html"
+        ], env=self.build_env())
+
     @Command('test-wpt',
              description='Run the web platform tests',
              category='testing')

tests/wpt/metadata/MANIFEST.json

@@ -14245,6 +14245,9 @@
       {
         "url": "/http/content_length.html"
       },
+      {
+        "url": "/infrastructure/failing-test.html"
+      },
       {
         "url": "/js/builtins/Array.DefineOwnProperty.html"
       },
@@ -17763,6 +17766,6 @@
     "deleted": [],
     "items": {}
   },
-  "rev": "badfd02aa085e25bd79f18902afbafcc8bc884b5",
+  "rev": "5bff693a497f200800d6d0dd6e3cc3556cc00bbe",
   "url_base": "/"
 }

tests/wpt/web-platform-tests

@@ -1 +1 @@
-Subproject commit badfd02aa085e25bd79f18902afbafcc8bc884b5
+Subproject commit 5bff693a497f200800d6d0dd6e3cc3556cc00bbe