Rspec test which is expecting an email to be sent to email

AdminEmailExpectation

it 'sends email to admin with error response' do
  VCR.use_cassette('external_service_response_cassette/invalid_requests', record: :new_episodes) do

    Hash.any_instance.stub(:value_from_params).and_raise(ExceptionType, "Failed to find key in params")
    
    params1 = 'AdminMailer'
    params2 = 'errors'
    params3 = 'Error message: There has been an error'
    SendEmailWorker.should_receive(:perform_async).with(params1, params2, params3).exactly(1).times

    get :request_external_service, { parameters }
  end
end