address code review changes and fix test

Author: anarchivist

spec/requests/preview/preview_spec.rb

@@ -3,23 +3,24 @@
 RSpec.describe Preview::PreviewController, type: :request do
   describe 'GET /preview' do
     context 'with the preview environment enabled' do
-      it 'shows a test UI in when SERVE_TEST_UI is true' do
+      before do
         allow(ENV).to receive(:[]).with('SERVE_TEST_UI').and_return(true)
+      end
+
+      it 'shows a test UI in when SERVE_TEST_UI is true' do
         get preview_path
         expect(response).to have_http_status(:ok)
         expect(response.content_type).to start_with('text/html')
       end
 
       context 'sets the API URL correctly' do
         it 'sets the url for staging API in production' do
-          allow(ENV).to receive(:[]).with('SERVE_TEST_UI').and_return(true)
           allow(Rails.env).to receive(:production?).and_return(true)
           get preview_path
           expect(assigns(:api_url)).to eq('https://galc-api.ucblib.org')
         end
 
         it 'sets the url for API to be localhost in dev/test' do
-          allow(ENV).to receive(:[]).with('SERVE_TEST_UI').and_return(true)
           allow(Rails.env).to receive(:production?).and_return(false)
           get preview_path
           expect(assigns(:api_url)).to eq('http://localhost:3000')

spec/views/preview/preview/index.html.erb_spec.rb

@@ -1,6 +1,6 @@
 require 'rails_helper'
 
-RSpec.describe 'preview/preview#index', type: :view do
+RSpec.describe 'preview/preview/index', type: :view do
   let(:endpoint) { 'https://galc.oski.cat' }
 
   it 'sets the API endpoint' do