Test Article creation within Rails/Rspec

The controller redirects to the article#show once created. I included let(:article) { create :article } as I would otherwise get the error

Failure/Error: expect(response).to redirect_to article_path(article)
NameError:
undefined local variable or method `article' for #<RSpec::ExampleGroups::ArticlesController::Create::ValidParams "creates an article" (./spec/controllers/article_controller_spec.rb:27)>`.

Anyway, I am receiving the below so it seems like creating the extra article causes this I think:

Failure/Error: expect(response).to redirect_to article_path(article)
Expected response to be a redirect to <http://test.host/articles/4> but was a redirect to <http://test.host/articles/3>.
Expected "http://test.host/articles/4" to be === "http://test.host/articles/3".

articles_controller_spec.rb

require 'rails_helper'
RSpec.describe ArticlesController, type: :controller do
user = FactoryBot.create(:user)
user.confirm
describe '#create' do
before do
sign_in user
end
context 'valid params' do
let(:article) { create :article }
let(:params) {
{
article: {
title: 'New article title',
body: 'New article body',
status: 'public',
created_at: Time.now,
updated_at: Time.now,
user:
},
}
}
it 'creates an article' do
# debugger
post :create, params: params
expect(response).to redirect_to article_path(article)
end
end
end
end

articles_controller

class ArticlesController < ApplicationController
def index
@articles = Article.all
end
# Rails ACTIVERECORD method :include which loads associative records in
# advance and limits the number of SQL queries made to the DB.
# To improve performance.
def home
@user = User.includes(:articles, :comments)
end
def show
@article = Article.find(params[:id])
@comment = @article.comments.order(updated_at: :desc)
@article.update(views: @article.views + 1)
mark_notifications_as_read
end
def new
@article = Article.new
end
def create
@article = Article.new(article_params)
@article.user = current_user
if @article.save
redirect_to @article, notice: 'Article created successfully'
else
render :new, status: :unprocessable_entity
end
end
def edit
@article = Article.find(params[:id])
end
def update
@article = Article.find(params[:id])
if @article.update(article_params)
redirect_to @article, notice: 'Article updated successfully'
else
render :edit, status: :unprocessable_entity
end
end
def destroy
@article = Article.find(params[:id])
@article.destroy
redirect_to articles_path, status: :see_other, notice: 'Article deleted successfully'
end
# All private methods ensure only the class they're initialized in can access the method
private
def article_params
params.require(:article).permit(:title, :body, :status)
end
def mark_notifications_as_read
return unless current_user
notifications_to_mark_as_read = @article.notifications_as_article.where(recipient: current_user)
notifications_to_mark_as_read.update_all(read_at: Time.zone.now)
end
end

factories/article

FactoryBot.define do
factory :article do
title { Faker::Lorem.words(number: 2) }
body { Faker::Lorem.paragraphs }
created_at { Faker::Time.between(from: DateTime.now - 1, to: DateTime.now) }
updated_at { Faker::Time.between(from: DateTime.now - 1, to: DateTime.now) }
status { 'public' }
association :user, factory: :user
end
end

routes.rb

Rails.application.routes.draw do
root 'articles#home'
get 'search', to: 'search#index'
devise_for :users, controllers: {
sessions: 'users/sessions',
registrations: 'users/registrations'
}
# allows for chained url routes
# eg. /posts/1/comments/4
resources :articles do
resources :comments
end
end

rails routes

                articles GET    /articles(.:format)                                                                               articles#index
POST   /articles(.:format)                                                                               articles#create
new_article GET    /articles/new(.:format)                                                                           articles#new
edit_article GET    /articles/:id/edit(.:format)                                                                      articles#edit
article GET    /articles/:id(.:format)                                                                           articles#show
PATCH  /articles/:id(.:format)                                                                           articles#update
PUT    /articles/:id(.:format)                                                                           articles#update
DELETE /articles/:id(.:format)                                                                           articles#destroy

Regarding your second error

Failure/Error: expect(response).to redirect_to article_path(article)
Expected response to be a redirect to <http://test.host/articles/4> but was a redirect to <http://test.host/articles/3>.
Expected "http://test.host/articles/4" to be === "http://test.host/articles/3".

The problem is the expect block. Since you are doing a POST request to create a new record, the expectation should check that there's an increase in the record count not being redirected to another record, the one created on the let block.

I would recommed changing your test to something like this:

  it 'creates an article' do
expect { post :create, params: }.to change { Article.count }.by(1)
expect(response).to have_http_status(200)
end