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Ruby

Shawn Wilson
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Shawn Wilson
iOS Development Techdegree Student 7,049 Points
Posted by Shawn Wilson
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Shawn Wilson
iOS Development Techdegree Student 7,049 Points

!let undefined method error while trying to run test

hey all im trying to run a spec for the ODOT sample project in ruby basics.... here is the command line error i get:

Failure/Error: let!(:todo_list) { TodoList.create(title: "Grocery list", description: "Groceries") } NoMethodError: undefined method let!' for #<RSpec::Core::ExampleGroup::Nested_1:0x007fdc06c90ab0> # ./spec/features/todo_items/index_spec.rb:5:inblock (2 levels) in <top (required)>'

i have tried to replace the !let with just let, but get same result. i hve retraced the video for a few hours but i am running a newer version of rails so this may be the issue. here is the test code below: 

require 'spec_helper'

describe "Viewing todo items" do
    it "displays no items when a todo list is empty" do
        let!(:todo_list) { TodoList.create(Title: "Grocery list", Description: "Groceries") }
        visit "/todo_lists"
        witih "#todo_list_#{todo_list.id}" do
            click_link "List Items"
        end
        expect(page).to have_content("TodoItems#index")
    end
end

im trying to read the error but cant quite grasp it i know it tells me the problem in the error message and i know it is boiling down to the let! but not sure how to proceed. ive tried to refrence google and rails guide but to no avail. is this likely an issue that im running a newer version of ROR over what is being shown in the demonstration?

1 Answer

Maciej Czuchnowski
Maciej Czuchnowski
36,441 Points
Maciej Czuchnowski
Maciej Czuchnowski
36,441 Points

These let statements should not be placed inside the it blocks, only inside the higher level describe blocks. Just move it two lines up and it should work :)

Shawn Wilson
seal-mask
.a{fill-rule:evenodd;}techdegree
Shawn Wilson
iOS Development Techdegree Student 7,049 Points
Shawn Wilson
.a{fill-rule:evenodd;}techdegree
Shawn Wilson
iOS Development Techdegree Student 7,049 Points

so do i move the entire line up two lines above the it block or just the let!? is this something that has changed between versions of rails? because in the tutorial it is where i have it placed now and the test performs just fine.

just trying to understand how the syntax has evolved.

Maciej Czuchnowski
Maciej Czuchnowski
36,441 Points
Maciej Czuchnowski
Maciej Czuchnowski
36,441 Points

Well, I just tested this in my own app. I got this error: let` is not available from within an example (e.g. an `it` block) or from constructs that run in the scope of an example (e.g. `before`, `let`, etc). It is only available on an example group (e.g. a `describe` or `context` block).

I use rspec-rails 3.2.1. So this runs fine, since the whole "let" is within the describe block:

  describe "GET #index" do
    let(:super_product) { Product.create(title: "Super Sledge", description: "Preferred melee weapon of supermutants", price: 99.99, image_url: "sledge.jpg") }

    it "assigns a @products variable" do
      product = Product.create!(valid_attributes)
      get :index
      expect(assigns(:products)).to eq([product, super_product])
    end
  end

But this gives me the error I quoted because it's in the it block:

  describe "GET #index" do

    it "assigns a @products variable" do
      let(:super_product) { Product.create(title: "Super Sledge", description: "Preferred melee weapon of supermutants", price: 99.99, image_url: "sledge.jpg") }
      product = Product.create!(valid_attributes)
      get :index
      expect(assigns(:products)).to eq([product, super_product])
    end
  end
Maciej Czuchnowski
Maciej Czuchnowski
36,441 Points
Maciej Czuchnowski
Maciej Czuchnowski
36,441 Points

I you're serious about learning RSpec, you should check out this book: https://leanpub.com/everydayrailsrspec

Bear in mind that the creator of Rails hates Rspec and the whole "Prime stack":

http://words.steveklabnik.com/rails-has-two-default-stacks

http://www.rubyinside.com/dhh-offended-by-rspec-debate-4610.html