Nil不是Rspec的象征

Question

当我在本地主机上以开发模式运行时。一切正常，我可以轻松删除我的帖子。但我的要求规格却失败了。

我在运行测试时遇到此错误：

1) Posts when logged in should delete posts
     Failure/Error: expect{click_on "Usuń spot"}.to change(Post.count).by(1)
     TypeError:
       nil is not a symbol

posts_spec.rb

describe "when logged in" do
    let(:user) {FactoryGirl.create(:user)}
    let!(:post) {user.posts.create(content: "Brilliant! I just saw the most amazing ever. She looked so cute!")}
    content = "Example of spot post, for TDD. It's not real spot. Not yet."

    before(:each) {
      log_user(user)
    }

    it "should delete posts" do
      visit user_post_path(user, post)
      expect{click_on "Usuń spot"}.to change(Post.count).by(1)
    end

show.haml

=@post.content
=link_to "Usuń spot", [@user,@post], method: :delete

posts_controller.rb

  def show
    @user = current_user
    @post = @user.posts.find(params[:id])
  end

  def destroy
    @user = current_user
    @post = @user.posts.find_by_id(params[:id])
    @post.destroy

    flash[:success] = "Post destroyed"

    redirect_to root_url
  end

Answer 1

change需要一个块，因此可以对其进行两次评估以验证值的变化。

这应该有效：

expect{click_on "Usuń spot"}.to change{Post.count}.by(1)

Answer 2

change{Post, :count}.by(1)

是正确的语法。 documentation