Basic framework for devtools-based scrolling tests.

tools/chrome_remote_control/chrome_remote_control/tab.py

+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import json
+import time
+import websocket
+import socket
+
+class EvaluateException(Exception):
+  pass
+
+class Tab(object):
+  def __init__(self, browser, descriptor):
+    self._browser = browser
+    self._descriptor = descriptor
+    self._socket = websocket.create_connection(
+        descriptor["webSocketDebuggerUrl"]);
+    self._socket.settimeout(0.5)
+    self._next_request_id = 0
+
+  def __enter__(self):
+    return self
+
+  def __exit__(self, *args):
+    if self._socket:
+      self.Close()
+
+  def Close(self):
+    self._socket.close()
+    self._socket = None
+    self._browser = None
+
+  def _SyncRequest(self, req):
+    req["id"] = self._next_request_id
+    self._next_request_id += 1
+    self._socket.send(json.dumps(req))
+    while True:
+      try:
+        data = self._socket.recv()
+      except socket.error:
+        req["id"] = self._next_request_id
+        self._next_request_id += 1
+        self._socket.send(json.dumps(req))
+        continue
+      res = json.loads(data)
+      if "method" in res:
+        continue
+
+      if res["id"] != req["id"]:
+        continue
+      return res
+
+  def RuntimeEvaluate(self, expr):
+    request = {
+      "method": "Runtime.evaluate",
+      "params": {
+        "expression": expr,
+        "returnByValue": True
+        }
+      }
+    res = self._SyncRequest(request)
+    if res["result"]["wasThrown"]:
+      # TODO(nduca): propagate stacks from javascript up to the python
+      # exception.
+      raise EvaluateException(res["result"]["result"]["description"])
+    if res["result"]["result"]["type"] == 'undefined':
+      return None
+    return res["result"]["result"]["value"]
+
+  def BeginToLoadURL(self, url):
+    # In order to tell when the document has actually changed,
+    # we go to about:blank first and wait. When that has happened, we
+    # to go the new URL and detect the document being non-about:blank as
+    # indication that the new document is loading.
+    self.RuntimeEvaluate("document.location = 'about:blank';")
+    while True:
+      hr = self.RuntimeEvaluate("document.location.href")
+      if hr == "about:blank":
+        break
+      time.sleep(0.01)
+
+    self.RuntimeEvaluate("document.location = '%s';" % url)
+    while True:
+      hr = self.RuntimeEvaluate("document.location.href")
+      if hr != "about:blank":
+        break
+      time.sleep(0.01)
+
+  def WaitForDocumentReadyStateToBeComplete(self):
+    while True:
+      rs = self.RuntimeEvaluate("document.readyState")
+      if rs == 'complete':
+        break
+      time.sleep(0.01)
+
+  def WaitForDocumentReadyStateToBeInteractiveOrBetter(self):
+    while True:
+      rs = self.RuntimeEvaluate("document.readyState")
+      if rs == 'complete' or rs == 'interactive':
+        break
+      time.sleep(0.01)