--- a/testing/web-platform/tests/tools/webdriver/webdriver/client.py
+++ b/testing/web-platform/tests/tools/webdriver/webdriver/client.py
@@ -349,18 +349,23 @@ class UserPrompt(object):
     @text.setter
     @command
     def text(self, value):
         body = {"value": list(value)}
         self.session.send_session_command("POST", "alert/text", body=body)
 
 
 class Session(object):
-    def __init__(self, host, port, url_prefix="/", capabilities=None,
-                 timeout=None, extension=None):
+    def __init__(self,
+                 host,
+                 port,
+                 url_prefix="/",
+                 capabilities=None,
+                 timeout=None,
+                 extension=None):
         self.transport = transport.HTTPWireProtocol(
             host, port, url_prefix, timeout=timeout)
         self.capabilities = capabilities
         self.session_id = None
         self.timeouts = None
         self.window = None
         self.find = None
         self._element_cache = {}
@@ -368,16 +373,20 @@ class Session(object):
         self.extension_cls = extension
 
         self.timeouts = Timeouts(self)
         self.window = Window(self)
         self.find = Find(self)
         self.alert = UserPrompt(self)
         self.actions = Actions(self)
 
+    def __eq__(self, other):
+        return (self.session_id is not None and isinstance(other, Session)
+                and self.session_Id == other.session_id)
+
     def __enter__(self):
         self.start()
         return self
 
     def __exit__(self, *args, **kwargs):
         self.end()
 
     def __del__(self):