Comment 3 for bug 1426483

This is also true for /v2/meters/somemeter:

    - name: post meter error is JSON
      desc: https://bugs.launchpad.net/ceilometer/+bug/1426483
      xfail: true
      url: /v2/meters/apples
      method: POST
      request_headers:
          content-type: application/json
      data: ""
      status: 400
      response_headers:
          content-type: /application/json/
      response_json_paths:
          error_message:
              faulstring: 'Missing argument: "samples"'

The 400 response is correct, but there is no content-type header to indicate that the response is JSON and thus the response cannot be parsed as such.