Fix bug in mergetraces.py.

tools/cygprofile/mergetraces_unittest.py

 # Copyright 2014 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 mergetraces
 
-class GroupByProcessAndThreadIdTest(unittest.TestCase):
+class GroupByProcessAndThreadIdTestBasic(unittest.TestCase):
   def runTest(self):
     # (sec, usec, 'pid:tid', function address).
     input_trace = [
         (100, 10, '2000:2001', 0x5),
         (100, 11, '2000:2001', 0x3),
-        (100, 11, '2000:2000', 0x1),
-        (100, 12, '2001:2001', 0x6),
-        (100, 13, '2000:2002', 0x8),
-        (100, 13, '2001:2002', 0x9),
-        (100, 14, '2000:2000', 0x7)
+        (100, 13, '2000:1999', 0x8),
+        (100, 14, '2000:2000', 0x7),
+        (120, 13, '2001:2003', 0x9),
+        (150, 12, '2001:2004', 0x6),
+        (180, 11, '2000:2000', 0x1),
     ]
 
     # Functions should be grouped by thread-id and PIDs should not be
     # interleaved.
     expected_trace = [
         (100, 10, '2000:2001', 0x5),
         (100, 11, '2000:2001', 0x3),
-        (100, 11, '2000:2000', 0x1),
+        (100, 13, '2000:1999', 0x8),
         (100, 14, '2000:2000', 0x7),
-        (100, 13, '2000:2002', 0x8),
-        (100, 12, '2001:2001', 0x6),
-        (100, 13, '2001:2002', 0x9)
+        (180, 11, '2000:2000', 0x1),
+        (120, 13, '2001:2003', 0x9),
+        (150, 12, '2001:2004', 0x6),
     ]
 
     grouped_trace = mergetraces.GroupByProcessAndThreadId(input_trace)
 
     self.assertEqual(grouped_trace, expected_trace)
+
+class GroupByProcessAndThreadIdFailsWithNonUniqueTIDs(unittest.TestCase):
+  def runTest(self):
+    # (sec, usec, 'pid:tid', function address).
+    input_trace = [
+        (100, 10, '1999:2001', 0x5),
+        (100, 10, '1988:2001', 0x5),
+    ]
+
+    try:
+      mergetraces.GroupByProcessAndThreadId(input_trace)
+    except Exception:
+      return
+
+    self.fail('Multiple processes should not have a same thread-ID.')