Intermittent setup errors in wdspec tests (SessionNotCreatedException: session not created (500): Session is already started)

[jdm]

  ▶ Unexpected subtest result in /webdriver/tests/element_send_keys/interactability.py:
  │ ERROR [expected FAIL] test_hidden
  │   → setup error
  │ 
  │ capabilities = {}
  │ configuration = {'capabilities': {}, 'host': '127.0.0.1', 'port': 43687}
  │ request = <SubRequest 'session' for <Function 'test_hidden'>>
  │ 
  │     @pytest.fixture(scope="function")
  │     def session(capabilities, configuration, request):
  │         """Create and start a session for a test that does not itself test session creation.
  │     
  │         By default the session will stay open after each test, but we always try to start a
  │         new one and assume that if that fails there is already a valid session. This makes it
  │         possible to recover from some errors that might leave the session in a bad state, but
  │         does not demand that we start a new session per test."""
  │         global _current_session
  │     
  │         # Update configuration capabilities with custom ones from the
  │         # capabilities fixture, which can be set by tests
  │         caps = copy.deepcopy(configuration["capabilities"])
  │         caps.update(capabilities)
  │         caps = {"alwaysMatch": caps}
  │     
  │         # If there is a session with different capabilities active, end it now
  │         if _current_session is not None and (
  │                 caps != _current_session.requested_capabilities):
  │             _current_session.end()
  │             _current_session = None
  │     
  │         if _current_session is None:
  │             _current_session = webdriver.Session(
  │                 configuration["host"],
  │                 configuration["port"],
  │                 capabilities=caps)
  │         try:
  │ >           _current_session.start()
  │ 
  │ capabilities = {}
  │ caps       = {'alwaysMatch': {}}
  │ configuration = {'capabilities': {}, 'host': '127.0.0.1', 'port': 43687}
  │ request    = <SubRequest 'session' for <Function 'test_hidden'>>
  │ 
  │ tests/wpt/web-platform-tests/webdriver/tests/support/fixtures.py:150: 
  │ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
  │ tests/wpt/web-platform-tests/tools/webdriver/webdriver/client.py:429: in start
  │     value = self.send_command("POST", "session", body=body)
  │ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
  │ 
  │ self = <Session (disconnected)>, method = 'POST', url = 'session'
  │ body = {'capabilities': {'alwaysMatch': {}}}
  │ 
  │     def send_command(self, method, url, body=None):
  │         """
  │             Send a command to the remote end and validate its success.
  │     
  │             :param method: HTTP method to use in request.
  │             :param uri: "Command part" of the HTTP request URL,
  │                 e.g. `window/rect`.
  │             :param body: Optional body of the HTTP request.
  │     
  │             :return: `None` if the HTTP response body was empty, otherwise
  │                 the `value` field returned after parsing the response
  │                 body as JSON.
  │     
  │             :raises error.WebDriverException: If the remote end returns
  │                 an error.
  │             :raises ValueError: If the response body does not contain a
  │                 `value` key.
  │             """
  │         response = self.transport.send(
  │             method, url, body,
  │             encoder=protocol.Encoder, decoder=protocol.Decoder,
  │             session=self)
  │     
  │         if response.status != 200:
  │             err = error.from_response(response)
  │     
  │             if isinstance(err, error.InvalidSessionIdException):
  │                 # The driver could have already been deleted the session.
  │                 self.session_id = None
  │     
  │ >           raise err
  │ E           SessionNotCreatedException: session not created (500): Session is already started
  │ 
  │ body       = {'capabilities': {'alwaysMatch': {}}}
  │ err        = <SessionNotCreatedException http_status=500>
  │ method     = 'POST'
  │ response   = <Response status=500 error=<SessionNotCreatedException http_status=500>>
  │ self       = <Session (disconnected)>
  │ url        = 'session'
  │ 
  └ tests/wpt/web-platform-tests/tools/webdriver/webdriver/client.py:480: SessionNotCreatedException