code: def testMarketTiming(self):
      files = []
      instruments = ["VTI", "VEU", "IEF", "VNQ", "DBC", "SPY"]
      for year in range(2007, 2013 + 1):
          for symbol in instruments:
              fileName = "%s-%d-yahoofinance.csv" % (symbol, year)
              files.append(os.path.join("samples", "data", fileName))
  
      # The differences in the output are related to key ordering in dicts.
      if six.PY3:
          expected_output = "market_timing.output.37"
      else:
          expected_output = "market_timing.output.27"
  
      with common.CopyFiles(files, "."):
          code = """import sys
  sys.path.append('samples')
  import market_timing
  market_timing.main(False)
  """
          res = common.run_python_code(code)
          self.assertTrue(res.exit_ok())
          self.assertEqual(
              res.get_output_lines()[-10:],
              common.tail_file(expected_output, 10),
          )
  
imports: import os
  import six
  from testcases import common
label_desc: Use image node_id 8 for calling the SampleStratTestCase obj's underlying member method code with example usage: obj.testMarketTiming() without return types