old_contents: from __future__ import unicode_literals
  
  import unittest
  
  from pyaavso.formats.visual import VisualFormatWriter
  
  
  class VisualFormatWriterTestCase(unittest.TestCase):
      def test_writer_init(self):
          writer = VisualFormatWriter()
  
new_contents: from __future__ import unicode_literals
  
  import unittest
  from StringIO import StringIO
  
  from pyaavso.formats.visual import VisualFormatWriter
  
  
  class VisualFormatWriterTestCase(unittest.TestCase):
      """
      Tests for VisualFormatWriter class.
      """
      def test_write_header_obscode(self):
          """
          Check that observer code is written into file.
          """
          fp = StringIO()
          writer = VisualFormatWriter(fp, 'XYZ')
          contents = fp.getvalue()
          self.assertIn("#OBSCODE=XYZ", contents)
  
subject: Test for obscode in file.