Smoke test for tracing infrastructure in PyAuto

chrome/test/functional/tracing/tracer.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 pyauto_tracing
+import pyauto
+import tab_tracker
+from timeline_model import TimelineModel
+
+import os
+
+
+class Tracer:

[Nirnimesh, 2012/07/31 23:39:10]

I think the convention is to have all classes derive from object.

Please repeat for all other classes.

+  """Controlls chrome and system tracing, returning a TimelineModel."""
+
+  def __init__(self, browser, tab_tracker):
+    """
+    Args:
+      browser: an instance of a PyUITest
+      tab_tracker: an instance of a TabTracker
+    """
+    self._browser = browser
+    self._tab_tracker = tab_tracker
+    self._tab_uuid = tab_tracker.CreateTab('chrome://tracing')
+
+    # TODO(eatnumber): Find a way to import timeline_model_shim.js from within
+    # TimelineModelProxy
+    # I'm not happy with importing timeline_model_shim.js
+    # here. I'd rather pull it in from within TimelineModelProxy.
+    # tracing_test.js depends on timeline_model_shim.js however.
+    files = ['timeline_model_shim.js', 'tracer.js']
+    for fileName in files:
+      file_js = None

[Nirnimesh, 2012/07/31 23:39:10]

Not necessary. Either line 34 fails and throws an exception or line 35 succeeds.

+      with open(os.path.join(os.path.dirname(__file__), fileName), 'r') as fd:
+        file_js = fd.read()
+      self._ExecuteJavascript(file_js);
+
+  def __del__(self):
+    self._tab_tracker.ReleaseTab(self._tab_uuid)
+
+  def _ExecuteJavascript(self, js):
+    return self._browser.ExecuteJavascript(
+        js = js,
+        windex = self._tab_tracker.GetWindowIndex(),
+        tab_index = self._tab_tracker.GetTabIndex(self._tab_uuid)
+    )
+
+  def BeginTracing(self, system_tracing=True):
+    """Start tracing.
+
+    Args:
+      system_tracing: whether or not to gather system traces along with chrome
+      traces.
+    """
+    self._ExecuteJavascript(
+        """
+            window.domAutomationController.send(
+                window.pyautoRecordTrace(%s)
+            );
+        """ % (
+            'true' if system_tracing else 'false'

[Nirnimesh, 2012/07/31 23:39:10]

This can fit in previous line. Also the next line

+        )
+    )
+
+  def EndTracing(self):
+    """End tracing and return a TimelineModel.
+
+    Returns:
+      an instance of a TimelineModel which contains the results of the trace
+    """
+    return TimelineModel(
+        js_executor = self._ExecuteJavascript.__get__(self, Tracer),
+        shim_id = self._ExecuteJavascript('tracingController.endTracing();')
+    )
+
+
+class TracerFactory:
+  """A TracerFactory is used to produce a Tracer.
+
+  It's recommended to use the same TracerFactory to produce all Tracers so that
+  the same TabTracker can be used throughout
+
+  Args:
+    browser: an instance of a PyUITest
+  """
+  def __init__(self, browser):
+    self._tab_tracker = tab_tracker.TabTracker(browser)
+    self._browser = browser
+
+  def Produce(self):
+    """Produce an instance of a Tracer"""
+    return Tracer(self._browser, self._tab_tracker)