The use of let (:chef_run)

[trekr5]

Hello,

I'm new to Chef and Chef testing using ChefSpec.

I've set up my first test with ChefSpec with the following default_spec.rb

require 'chefspec'
require 'spec_helper'

describe 'tesr::default' do

    let(:chef_run) {ChefSpec::ChefRunner.new.converge('tesr::default')}
  

    it 'deploy file' do

     
           expect(chef_run).to deploy_deploy("#{ node[:tesr][:rubygem_host]}")
    end

end   

My default.rb is:

http_deploy "gginfrausermanager-1.0.149" do

    url "http://nuget.prod.praetor.service/artifactory/simple/int-gem/gems"
   
    path node[:tesr][:rubygem_host]
 
    path "/"
   
end

and in attributes/default.rb:

default[:tesr][:rubygem_host] = "http://nuget.prod.praetor.service/artifactory/simple/int-gem/gems"

However when I run this ChefSpec test, I get the following error:
Failures:

1) tesr::default deploy file
   Failure/Error: let(:chef_run) {ChefSpec::ChefRunner.new.converge('tesr::default')}
NameError:
unintialized constant ChefSpec::ChefRunner

1 example, 1 failure

I have done the following:-
1) installed gem ChefSpec -v 3.1.4 and 4.1.1 (installed 3.1.4 because it was said to fix uninitialized error)
2) have also used ChefSpec::Runner instead of ChefSpec::ChefRunner
3) Chef::Exceptions::CookbookNotFound (Chocolatey cookbook not found even though this cookbook is in Berksfile)

Can anyone throw any light on this?

Many thanks