'Test for the behavior of _has_changed for FileField. The value of data will
more than likely come from request.FILES. The value of initial data will
likely be a filename stored in the database. Since its value is of no use to
a FileField it is ignored.'

def test_filefield_changed(self):

    f = FileField()
    self.assertFalse(f._has_changed(u'', None))
    self.assertTrue(f._has_changed(u'', {u'filename': u'resume.txt', u'content': u'My    resume'}))
    self.assertFalse(f._has_changed(u'resume.txt', None))
    self.assertTrue(f._has_changed(u'resume.txt', {u'filename': u'resume.txt', u'content': u'My    resume'}))
