Rspec doesn't see my model Class. uninitialized constant error

In rails 4.x and later (rspec-rails 3.1.0 and later) add this to the top of each of your spec files:

require "rails_helper"  # this

not

require "spec_helper"   # not this

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Your spec_helper file is missing some important commands. Specifically, it's not including config/environment and initializing rspec-rails.

You can add the following lines to the start of your spec/spec_helper.rb file

ENV["RAILS_ENV"] ||= 'test'
require File.expand_path("../../config/environment", __FILE__)
require 'rspec/rails'
require 'rspec/autorun'

or you can just run

rails generate rspec:install

and overwrite your spec_helper with one generated for use with rspec-rails.

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You might also like to add --require rails_helper in your .rspec file so that it looks like this.

--color
--require spec_helper
--require rails_helper

You won't need to require rails_helper in all your specs, after this.

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I'm using Rails 5.0.0.1. Here's how I resolved this concern.

On your Gemfile, please add -> gem 'rspec-rails', ">= 2.0.0.beta"

Like so,

group :development, :test do
  gem 'rspec-rails', ">= 2.0.0.beta"
end

Reason: if the rspec-rails is not added and when you execute the rspec command, it will generate this error -> "cannot load such file -- rails_helper"

Now, execute this command on the terminal.

bundle install

Once bundle command went good, execute the rails generate. Like so,

rails generate rspec:install

Reason: this command will create a new .rspec(hit overwrite when prompted), spec/rails_helper.rb and spec/spec_helper.rb

Now, at this point, rspec should pretty much run properly. However, if you encounter an error where in the model is not found e.g. cannot load such file -- idea, try adding this on top of your spec/spec_helper.rb

require 'rubygems'
ENV["RAILS_ENV"] ||= 'test'
require File.expand_path("../../config/environment", __FILE__)

Reason: seems that spec_helper is not loading the Rails environment. We're requiring it.

Hope this helps!

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If other answers under this question don't work, try:

Check if there is any typo in the file name or class name (they should match)

Other wise,

Check your config/environment/test.rb file, see if there is config.eager_load = false, set it to true.

You should check in the written order since you don't want to solve the issue with the typo laying there.

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None of the answers above quite hit the nail on the head for me, or weren't quite explicit enough with where lines of code needed to be placed. I'm using rails 6.0.2 and rspec-rails 4.1.0 and found two options that solved the issue.

Add the line require 'rails_helper' to the top of each spec file that you need to run. Add the line require 'rails_helper' to the top of the spec/spec_helper.rb file to make the rails helper file available in all tests.

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Things have moved a bit since this thread has been created, I have experienced the uninitialized constant ClassName (NameError) error too using Ruby 2.1, Rails 4.2, rspec-rails 3.3.

I have solved my problems reading the rspec-rails gem documentation :

https://github.com/rspec/rspec-rails#model-specs

where it confirms what Swards says about requiring "rails_helper" not "spec_helper" anymore.

Also my model specification looks more like the one from the gem docs

RSpec.describe Url, :type => :model do
    it 'is invalid without first_name', :focus => true do
        client = Client.new
        client.should_not be_valid
    end
end

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Factories folder define in your app

FactoryBot.define do
  factory :user_params , :class => 'User' do
    username 'Alagesan'
    password '$1234@..'

  end
end

Your Controller RSpec file:

it 'valid params' do
  post :register, params: {:user => user_params } 
end

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