old_contents: #!/usr/bin/env python
  
  try:
      import unittest2 as unittest
  except ImportError:
      import unittest
  
  from csvkit import convert
  
  
  class TestConvert(unittest.TestCase):
  
      def test_guess_fixed(self):
          self.assertEqual('fixed', convert.guess_format('testdata'))
  
      def test_guess_xls(self):
          self.assertEqual('xls', convert.guess_format('testdata.xls'))
  
      def test_guess_xls_uppercase(self):
          self.assertEqual('xls', convert.guess_format('testdata.XLS'))
  
      def test_guess_xlsx(self):
          self.assertEqual('xlsx', convert.guess_format('testdata.xlsx'))
  
      def test_guess_csv(self):
          self.assertEqual('csv', convert.guess_format('testdata.csv'))
  
      def test_guess_dbf(self):
          self.assertEqual('dbf', convert.guess_format('testdata.dbf'))
  
      def test_guess_json(self):
          self.assertEqual('json', convert.guess_format('testdata.json'))
  
new_contents: #!/usr/bin/env python
  
  try:
      import unittest2 as unittest
  except ImportError:
      import unittest
  
  from csvkit import convert
  
  
  class TestConvert(unittest.TestCase):
  
      def test_guess_fixed(self):
          self.assertEqual('fixed', convert.guess_format('testdata'))
  
      def test_guess_xls(self):
          self.assertEqual('xls', convert.guess_format('testdata.xls'))
  
      def test_guess_xls_uppercase(self):
          self.assertEqual('xls', convert.guess_format('testdata.XLS'))
  
      def test_guess_xlsx(self):
          self.assertEqual('xlsx', convert.guess_format('testdata.xlsx'))
  
      def test_guess_csv(self):
          self.assertEqual('csv', convert.guess_format('testdata.csv'))
  
      def test_guess_dbf(self):
          self.assertEqual('dbf', convert.guess_format('testdata.dbf'))
  
      def test_guess_json(self):
          self.assertEqual('json', convert.guess_format('testdata.json'))
  
      def test_guess_invalid(self):
          self.assertEqual(None, convert.guess_format('testdata.invalid'))
  
subject: Increase test coverage