如何为XML方法设置Rails集成测试？

require 'test_helper'

class ApiControllerTest< ActionDispatch::IntegrationTest
  setup do
    @user = users(:one)
    @headers = {
      'Content-Type' => 'application/xml',
      'Accept' => 'application/xml'
    }
  end

  test 'should create user with valid XML' do
    user_xml = <<-XML
      <?xml version="1.0" encoding="UTF-8"?>
      <user>
        <name>John Doe</name>
       <email>john.doe@example.com</email>
       <password>password</password>
      </user>
    XML

    post '/api/users', params: user_xml, headers: @headers

    assert_response :created
    assert_equal 'application/xml', response.content_type
    assert_equal 'John Doe', response.parsed_body['name']
    assert_equal 'john.doe@example.com', response.parsed_body['email']
  end

  test 'should return error with invalid XML' do
    user_xml = <<-XML
      <?xml version="1.0" encoding="UTF-8"?>
      <user>
        <name>John Doe</name>
       <email>john.doe@example.com</email>
      </user>
    XML

    post '/api/users', params: user_xml, headers: @headers

    assert_response :unprocessable_entity
    assert_equal 'application/xml', response.content_type
    assert_equal 'Password can\'t be blank', response.parsed_body['errors']['password']
  end
end