old_contents: # Copyright (c) 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 tempfile
  import os
  
  from trace_viewer.build import trace2html
  
  class Trace2HTMLTests(unittest.TestCase):
    def test_writeHTMLForTracesToFile(self):
      with tempfile.NamedTemporaryFile(mode='w', delete=False) as tmpfile:
        big_trace_path = os.path.join(os.path.dirname(__file__),
                                      '..', '..', 'test_data', 'big_trace.json')
        res = trace2html.WriteHTMLForTracesToFile([big_trace_path], tmpfile)
new_contents: # Copyright (c) 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 tempfile
  import os
  
  from trace_viewer.build import trace2html
  
  class Trace2HTMLTests(unittest.TestCase):
    def test_writeHTMLForTracesToFile(self):
      with tempfile.NamedTemporaryFile(mode='w', delete=False) as tmpfile:
        simple_trace_path = os.path.join(os.path.dirname(__file__),
                                      '..', '..', 'test_data', 'simple_trace.json')
        big_trace_path = os.path.join(os.path.dirname(__file__),
                                      '..', '..', 'test_data', 'big_trace.json')      
        res = trace2html.WriteHTMLForTracesToFile([big_trace_path, simple_trace_path], tmpfile)
subject: Improve trace2html_unittest