How to use the gftools.util.google_fonts.FullnameFor function in gftools

name: The name of the family.
    font: A font record from a METADATA.pb.
    ttf: A fontTools.ttLib.TTFont for the font.
  Returns:
    A list of ResultMessageTuple for tests performed.
  """
  results = []

  style = font.style
  weight = font.weight
  full_font_file = os.path.join(path, font.filename)

  expectations = [('family', fonts.NAME_FAMILY, name),
                  ('postScriptName', fonts.NAME_PSNAME, fonts.FilenameFor(
                      name, style, weight)), ('fullName', fonts.NAME_FULLNAME,
                                              fonts.FullnameFor(
                                                  name, style, weight))]

  for (friendly_name, name_id, expected) in expectations:
    # If you have lots of name records they should ALL have the right value
    actuals = fonts.ExtractNames(ttf, name_id)
    for (idx, actual) in enumerate(actuals):
      results.append(
          ResultMessageTuple(expected == actual,
                             '%s %s/%d \'name\' %s[%d] expected %s, got %s' %
                             (name, style, weight, friendly_name, idx, expected,
                              actual), full_font_file,
                             _FixBadNameRecord(friendly_name, name_id,
                                               expected)))

    # should have at least one actual
    if not actuals:

path: A directory containing a METADATA.pb file.
  Returns:
    A list of ResultMessageTuple, one per validation performed.
  """
  results = []
  metadata = fonts.Metadata(path)
  name = metadata.name

  for font in metadata.fonts:
    # We assume style/weight is correct in METADATA
    style = font.style
    weight = font.weight
    values = [('name', name, font.name), ('filename', fonts.FilenameFor(
        name, style, weight, '.ttf'), font.filename),
              ('postScriptName', fonts.FilenameFor(name, style, weight),
               font.post_script_name), ('fullName', fonts.FullnameFor(
                   name, style, weight), font.full_name)]

    for (key, expected, actual) in values:
      if expected != actual:
        results.append(
            _SadResult('%s METADATA %s/%d %s expected %s, got %s' %
                       (name, style, weight, key, expected, actual), path,
                       _FixMetadata(style, weight, key, expected)))

  if not results:
    results.append(
        _HappyResult('METADATA name consistently derived from "%s"' % name,
                     path))

  return results