Smoke test for tracing infrastructure in PyAuto

chrome/test/functional/tracing.py

+#!/usr/bin/env python
+# Copyright (c) 2011 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 unittest
+
+import pyauto_functional
+import pyauto

[nduca, 2012/07/13 17:36:08]

Lets split this into timeline_model.pyand tracing_smoke_test.py

Tracing smoke test should just record a trace and verify that there is at least
one process named CrBrowserMain.

Sg?

+import inspect
+import json
+import string
+
+class TimelineModel:

[nduca, 2012/07/13 09:47:56]

TimelineModelProxy

+  def __init__(self, test):

[nduca, 2012/07/13 09:47:56]

test -> automationController?

So you're initializing this with the assumption that the model is remotely
stored in profilingView.

Its cleaner to separate these concerns up front:

class TimelineModelProxy:
   def __init__(self, automationController, remoteObjectName):
     self._remoteObjectName = remoteObjectName;
     self._automationController = automationController;

# Alias TimelineModel to TimelineModelProxy for convenience
TimelineModel = TimelineModelProxy

+    self._test = test
+
+  # Do note that the JSON serialization process removes cyclic references.
+  # TODO(eatnumber) regenerate these cyclic references on deserialization.
+  def __js_call__(self, name, *args):

[nduca, 2012/07/13 09:47:56]

python convention say

def _js_call(self, name, *args)

sanity says
name -> method_name

+    return json.loads(self._test.ExecuteJavascript("""
+      var self = profilingView.timelineView.model;
+      var res = self['%s'].apply(self, JSON.parse('%s'));

[nduca, 2012/07/13 09:47:56]

why [%s]?

var res = %s.%s(%s)" % (self._remoteObjectName, methodName,
",".join([stringifyForJavascript(x) for x in args]))

+      window.domAutomationController.sendJSON(
+        JSON.stringify(JSON.stringify(res))

[nduca, 2012/07/13 09:47:56]

Probably worth setting up some basic error handling here so things dont explode
mysteriously if on you.

try {
  var res = model.method(args);
  sendstringified({success: res);
} catch(e) {
  stringify e
  send failure
}


and, on the python side, if you get fail

  throw Exception(js error);


To stringify a javascript exception you need to handle these three different
exception "flavors":
  if (typeof(e) == "string") {
    return e;
  } else if(e.stack) {
    return e.stack;
  } else {
     return e.message;
  }

+      );
+    """ % (
+      # Poor man's string escape.
+      string.replace(name, "'", "\\'"),

[nduca, 2012/07/13 09:47:56]

make this a method called escapeForJavascriptExecution so that you can deal with
complications that arise later.... and so you can do the right thing to method
args, as noted above. :)

+      string.replace(json.dumps(args), "'", "\\'")
+    ), 0, self._test.trace_win))
+
+  def getAllThreads(self):
+    return self.__js_call__(inspect.stack()[0][3]);

[nduca, 2012/07/13 09:47:56]

Too magic. Hard code it. Also, does PyAuto not follow google python style guide?
http://google-styleguide.googlecode.com/svn/trunk/pyguide.html#Naming

get_all_threads is what style guide say

+
+  def getAllCpus(self):
+    return self.__js_call__(inspect.stack()[0][3]);
+
+  def getAllProcesses(self):
+    return self.__js_call__(inspect.stack()[0][3]);
+
+  def getAllCounters(self):
+    return self.__js_call__(inspect.stack()[0][3]);
+
+class TraceTest(pyauto.PyUITest):
+  def setUp(self):
+    super(TraceTest, self).setUp()
+    self.trace_win = self.GetBrowserWindowCount()
+    self.OpenNewBrowserWindow(False)
+    self.NavigateToURL('chrome://tracing', self.trace_win)

[nduca, 2012/07/13 09:47:56]

do we know if NavigateToURL waits for the DOMContentLoaded event? E.g. are we
sure that executejavascript runs with the tracing scripts already loaded?

[Russ Harmon, 2012/07/13 23:24:24]

Other tests do it this way, so I'd assume yes.

+    self.ExecuteJavascript("""
+      tracingController.addEventListener("traceEnded", function() {

[nduca, 2012/07/13 09:47:56]

single quotes in javascript

+        window.domAutomationController.send("");

[nduca, 2012/07/13 09:47:56]

So if you pair this with the codereview I just posted
(http://codereview.appspot.com/6343106/) you should be able to do the following
from here:

window.pyauto_timeline_model = new TimleineModel();
var events = [tracingController.traceData];
if (tracingController.supportsSystemTracing)
  events.push(tracingControler.systemTraceData);
window.pyauto_timeline_model.importTraces(events);

Then, you can say
   this.model = new TimeineModelProxy(self, "window.pyauto_timeline_model")

+      });
+      window.domAutomationController.send("");
+    """, 0, self.trace_win)
+
+  def tearDown(self):
+    self.CloseBrowserWindow(self.trace_win)
+    self.trace_win = None

[nduca, 2012/07/13 09:47:56]

presumably this is _trace_win since you probably dont want folks subclassing
this test to use that member

+    super(TraceTest, self).tearDown()
+
+  def _BeginTracing(self):
+    # TODO(nduca) Make the chrome tracing ui easier to automate
+    self.ExecuteJavascript("""
+      tracingController.beginTracing(true);
+      window.domAutomationController.send("");
+    """, 0, self.trace_win)
+
+  def _EndTracing(self):
+    # TODO(nduca) Make the chrome tracing ui easier to automate
+    self.ExecuteJavascript("""
+      tracingController.endTracing();
+    """, 0, self.trace_win)
+    return TimelineModel(self);

[nduca, 2012/07/13 09:47:56]

What in the test does this cause us to wait on the send inside traceEnded?

[Russ Harmon, 2012/07/13 23:24:24]

I hope I understand this question correctly.

ExecuteJavascript won't return until window.domAutomationController.send is
called. The endTracing() call will asynchronously cause the eventListener
registered on line 52 to be invoked, then causing this call to return.

+
+  def testBlah(self):
+    self._BeginTracing()
+    self.NavigateToURL('http://google.com')
+    model = self._EndTracing()
+
+
+if __name__ == '__main__':
+  pyauto_functional.Main()