Mock a singleton class In Ruby on Rails using Rspec [SOLVED] - ruby-on-rails

Question

Hi I Try to create a mock for follow class:
module EstablishmentsQueryService
class << self
def find_by_id(id)
Establishment.find_by!(id:)
rescue ActiveRecord::RecordNotFound
raise EstablishmentNotFoundError.new id
end
end
end
to try test my controller
# frozen_string_literal: true
module Api
module V1
# Controllewr to manager Establishments
class EstablishmentsController < Api::V1::ApiController
before_action :validate_id, only: %i[destroy update show]
before_action :load_establishment, only: %i[destroy update show]
def show; end
def create
#establishment = Establishment.new(establishment_params)
#establishment = EstablishmentService.save(#establishment)
render status: :created
end
def destroy
EstablishmentService.delete(#establishment)
end
def update
#establishment.attributes = establishment_params
#establishment = EstablishmentService.save(#establishment)
end
private
def validate_id
message = I18n.t('establishment_controller.id.invalid', id: params[:id])
UuidValidateService.call(params[:id], message)
end
def load_establishment
#establishment = EstablishmentsQueryService.find_by_id(params[:id])
end
def establishment_params
params.require(:establishment).permit(:name, :cnpj, :description)
end
end
end
end
follow my test:
# frozen_string_literal: true
require 'rails_helper'
RSpec.describe 'Api::V1::Establishments', type: :request do
describe 'GET /api/v1/establishments/:id' do
context 'when has establishment' do
let(:establishment) { build(:establishment, id: p, created_at: DateTime.now, updated_at: DateTime.now) }
before do
allow_any_instance_of(EstablishmentsQueryService).to receive(:find_by_id).and_return(establishment)
get "/api/v1/establishments/#{establishment.id}"
end
it 'then http status is ok' do
expect_status_is_ok
end
it 'has body equal to expected' do
except_field_by_field(establishment, body_to_open_struct, %i[id name cnpj description])
end
end
context 'when has no establishment' do
before do
get "/api/v1/establishments/#{UUID.new.generate}"
end
it 'then http status is not_found' do
expect_status_is_not_found
end
end
context 'when use invalid id' do
before { get "/api/v1/establishments/#{FFaker::Lorem.word}" }
it 'then http status is bad_request' do
expect_status_is_bad_request
end
end
end
describe 'PUT /api/v1/establishments/:id' do
let(:establishments_query_service) { allow(EstablishmentsQueryService) }
let(:establishments_service) { allow(EstablishmentsService) }
context 'when updated with success' do
let(:establishment) { build(:establishment) }
let(:id) { UUID.new.generate }
before do
establishments_query_service.to receive(:find_by_id) { |p| build(:establishment, id: p, created_at: DateTime.now, updated_at: DateTime.now) }
establishments_service.to receive(:save) do |p|
to_return = p
to_return.created_at = DateTime.now
to_return.updated_at = DateTime.now
end
put "/api/v1/establishments/#{id}"
end
it 'then http status is ok' do
expect_status_is_ok
end
it 'has body equal to expected' do
actual = body_to_open_struct
except_field_by_field(establishment, actual, %i[name cnpj description])
expected(actual.id).to eq(id)
end
end
context 'when has no establishment' do
end
context 'when has constraint violation' do
end
end
describe 'DELETE /api/v1/establishments/:id' do
end
describe 'POST /api/v1/establishments' do
end
end
If I work using allow_any_instance_of a test ignore configuration, use a real configuration and fails because has no data stores. If I use double I received a follow error:
Api::V1::Establishments GET /api/v1/establishments/:id when has establishment then http status is ok
Failure/Error: allow_any_instance_of(EstablishmentsQueryService).to receive(:find_by_id).and_return(establishment)
EstablishmentsQueryService does not implement #find_by_id
I think the right away is user allow_any_instance_of because this config is for static methods, but didn't work
how can I mock my class to test my controller? I using Ruby 3.1.2, rails 7.0.3 and rspec-rails 5.1.2
thank you

Answer 1

I found my problem, I forgot to definie expected params in my confi using with()
allow(EstablishmentsQueryService).to receive(:find_by_id).with(establishment.id).and_return(establishment)