click_link rspec test not finding tag by id

Question

I've already added the reply-to-microposts functionality to Michael Hartl's Rails 3 Tutorial book, but I'm now trying to write the tests for them (I know I did it backwards). The replies addition works, but I'm trying to write the following test

1. create user and two posts from user
2. create other_user and two posts from other_user
3. have user follow other_user
4. check that user's home page feed includes other_user's post
5. ...

My tests are currently failing at step four. Below is the snippet from the spec file, the failure error, and the link to my repo. (user is defined before this describe, but within the scope of this block)

describe "replying to a micropost" do
    let (:other_user) { FactoryGirl.create(:user) }
    let (:first_post) { FactoryGirl.create(:micropost, user: other_user, content: "Whatever.") }
    let (:second_post) { FactoryGirl.create(:micropost, user: other_user, content: "Nevermind.") }

    before do
        user.follow!(other_user)
        visit root_path
    end

    it "should render the posts from other user" do
        page.should have_selector("li##{first_post.id}", text: first_post.content)
        page.should have_selector("li##{second_post.id}", text: second_post.content)
    end


Failures:

  1) Static pages Home page for signed-in users replying to a micropost should render the posts from other user
     Failure/Error: page.should have_selector("li##{first_post.id}", text: first_post.content)
       expected css "li#203" with text "Whatever." to return something
     # ./spec/requests/static_pages_spec.rb:85:in `block (5 levels) in <top (required)>'

Finished in 3.43 seconds
17 examples, 1 failure

Failed examples:

rspec ./spec/requests/static_pages_spec.rb:84 # Static pages Home page for signed-in users replying to a micropost should render the posts from other user

Done.

https://github.com/johnklawlor/sample_app

Answer 1

In short, my tests failed because I need to user let! (let bang) in order to create the micropost at the time of the let! call. Using a simple let call (i.e. without the !) doesn't create the micropost until the page.should have_selector line, which is after the visit root_path call and therefore does not find the micropost on the page.

Here's how I figured it out... It's related to a statement iterated in this question regarding let vs before initializations, where s/he states, "For the method defined by let, the initialization code only runs if the example calls it." (source: stackoverflow.com/questions/5359558/when-to-use-rspec-let) In my example, first_post and second_post weren't being created until I called on their id's in the have_selector('li'... call, which means they aren't created until after the visit root_path call and therefore after the user's feed is built. The only thing I have to back up this assumption is that if you add some line like first_post.content=first_post.content (and the same for second_post) before the visit root_path call, the

tags are generated for the posts as attested by the page opened from save_and_open_page and by the passing tests. Inserting a line like first_post.content=first_post.content after visit root_path produces no li tags and failing tests.