[DO NOT COMMIT] Refactor systrace to support new clock sync design

systrace/systrace/systrace_unittest.py

Index: systrace/systrace/systrace_unittest.py
diff --git a/systrace/systrace/systrace_unittest.py b/systrace/systrace/systrace_unittest.py
new file mode 100755
index 0000000000000000000000000000000000000000..8a5ce36df6c3380862c145e1b5740dfa4cb7164c
--- /dev/null
+++ b/systrace/systrace/systrace_unittest.py
@@ -0,0 +1,108 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2016 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 logging
+from systrace import tracing_agent, tracing_controller
+
+
+class FakeTracingAgent(tracing_agent.TracingAgent):
+  def __init__(self, clock_sync=True):
+    super(FakeTracingAgent, self).__init__()
+    self._clock_sync = clock_sync
+    self._sync_seen = False
+  def StartAgentTracing(self):
+    pass
+  def StopAgentTracing(self):
+    pass
+  def GetResults(self):
+    return tracing_agent.TraceResults('trace-data',
+                                      'Sync' if self._sync_seen else 'NoSync',
+                                      True)
+  def SupportsExplicitClockSync(self):
+    return self._clock_sync
+  def RecordClockSyncMarker(self, *_):
+    if not self._clock_sync:
+      raise NotImplementedError
+    self._sync_seen = True
+
+def _GetSyncCount(controller):
+  return controller.GetResults().trace_data.count('clock_sync')
+
+class SystraceTest(unittest.TestCase):
+
+  def testStartTracing(self):
+    cont = tracing_controller.TracingController([])
+    self.assertFalse(cont.trace_in_progress)
+    cont.StartTracing()
+    self.assertTrue(cont.trace_in_progress)
+    cont.StopTracing()
+
+  def testStopFirst(self):
+    cont = tracing_controller.TracingController([])
+    self.assertRaises(AssertionError, cont.StopTracing)
+
+  def testDoubleStart(self):
+    cont = tracing_controller.TracingController([])
+    cont.StartTracing()
+    self.assertRaises(AssertionError, cont.StartTracing)
+    cont.StopTracing()
+
+  def testDoubleStop(self):
+    cont = tracing_controller.TracingController([])
+    cont.StartTracing()
+    cont.StopTracing()
+    self.assertRaises(AssertionError, cont.StopTracing)
+
+  def testNoAgents(self):
+    cont = tracing_controller.TracingController([])
+    cont.StartTracing()
+    cont.StopTracing()
+    self.assertEqual(_GetSyncCount(cont), 0)
+
+  def testNoSupportedAgents(self):
+    cont = tracing_controller.TracingController([FakeTracingAgent(False)])
+    cont.StartTracing()
+    cont.StopTracing()
+    self.assertEqual(_GetSyncCount(cont), 0)
+
+  def testOneSupportedAgent(self):
+    cont = tracing_controller.TracingController([FakeTracingAgent(False),
+                                                 FakeTracingAgent(True)])
+    cont.StartTracing()
+    cont.StopTracing()
+    self.assertEqual(_GetSyncCount(cont), 1)
+
+  def testTwoSupportedAgents(self):
+    cont = tracing_controller.TracingController([FakeTracingAgent(True),
+                                                 FakeTracingAgent(False),
+                                                 FakeTracingAgent(True)])
+    cont.StartTracing()
+    cont.StopTracing()
+    self.assertEqual(_GetSyncCount(cont), 2)
+
+  def testOutputs(self):
+    cont = tracing_controller.TracingController([FakeTracingAgent(True),
+                                                 FakeTracingAgent(False),
+                                                 FakeTracingAgent(True)])
+    cont.StartTracing()
+    results = cont.StopTracing()
+    self.assertEqual(results[0].trace_data, 'Sync')
+    self.assertEqual(results[1].trace_data, 'NoSync')
+    self.assertEqual(results[2].trace_data, 'Sync')
+
+  def testMultipleSyncCycles(self):
+    cont = tracing_controller.TracingController([FakeTracingAgent(True),
+                                                 FakeTracingAgent(False),
+                                                 FakeTracingAgent(True)])
+    cont.StartTracing()
+    cont._IssueClockSyncMarker()
+    cont.StopTracing()
+    self.assertEqual(_GetSyncCount(cont), 4)
+
+if __name__ == "__main__":
+  logging.getLogger().setLevel(logging.DEBUG)
+  unittest.main(verbosity=2)