Minitest Rails测试用例中异常URL的点符号含义排查

错误信息 #

AnswersControllerTest#test_should_destroy_answer [/Users/pitosalas/mydev/questionanswer/test/controllers/answers_controller_test.rb:47]:
Expected response to be a redirect to <http://www.example.com/questions/525858932> but was a redirect to <http://www.example.com/questions.525858932>.
Expected "http://www.example.com/questions/525858932" to be === "http://www.example.com/questions.525858932".

测试代码 #

test "should destroy answer" do
  assert_no_difference("Question.count") do
    delete question_answer_url(@question, @answer)
  end

  assert_redirected_to question_url(@question)
end

控制器代码 #

def destroy
  @question = Question.find(params[:question_id])
  @answer = Answer.find(params[:id])
  respond_to do |format|
    format.html do
      if !@answer.comments.empty?
        redirect_to questions_url(@question), notice: "First delete all the comments"
      elsif @answer.destroy
        redirect_to questions_url(@question), notice: "Answer was successfully destroyed."
      else
        redirect_to questions_url(@question), notice: "Answer could not be destroyed."
      end
    end
    format.json { head :no_content }
  end
end

问题解析 #

URL里的点符号是路由辅助方法使用错误导致的：

• 控制器中用了复数形式的questions_url，这个方法对应问题列表页的路由（/questions）。当你向它传入@question实例时，Rails会把实例ID识别为格式后缀（类似.html这类格式参数），因此生成了questions.525858932这种错误路径。
• 测试代码里用的question_url(@question)是单数形式，对应单个问题详情页的路由（/questions/:id），能正确生成带斜杠的标准路径。

修复方法 #

把控制器中所有的redirect_to questions_url(@question)替换成redirect_to question_url(@question)，或者直接写redirect_to @question（Rails会自动推断出对应的单个资源路由）。

内容的提问来源于stack exchange，提问作者pitosalas