code: def testContentLength_isInBytes(self):
      q = wrappers.Request(wtest.EnvironBuilder().get_environ())
      r = http_util.Respond(q, "爱", "text/plain")
      self.assertEqual(r.headers.get("Content-Length"), "3")
      q = wrappers.Request(wtest.EnvironBuilder().get_environ())
      r = http_util.Respond(q, "爱".encode("utf-8"), "text/plain")
      self.assertEqual(r.headers.get("Content-Length"), "3")
  
imports: import gzip
  import io
  import struct
  from unittest import mock
  from werkzeug import test
  from werkzeug import wrappers
  from tensorboard import test
  from tensorboard.backend import http_util
label_desc: Use image node_id 4 for calling the RespondTest obj's underlying member method code with example usage: obj.testContentLength_isInBytes() without return types