FIX: Properly support defaults for upload site settings.

spec/requests/admin/site_settings_controller_spec.rb

@@ -51,31 +51,49 @@ describe Admin::SiteSettingsController do
         expect(SiteSetting.test_setting).to eq('')
       end
 
-      it 'allows upload site settings to be updated' do
-        upload = Fabricate(:upload)
+      describe 'upload site settings' do
+        it 'can remove the site setting' do
+          SiteSetting.test_upload = Fabricate(:upload)
 
-        put "/admin/site_settings/test_upload.json", params: {
-          test_upload: upload.url
-        }
+          put "/admin/site_settings/test_upload.json", params: {
+            test_upload: nil
+          }
 
-        expect(response.status).to eq(200)
-        expect(SiteSetting.test_upload).to eq(upload)
+          expect(response.status).to eq(200)
+          expect(SiteSetting.test_upload).to eq(nil)
+        end
 
-        user_history = UserHistory.last
+        it 'can reset the site setting to the default' do
+          SiteSetting.test_upload = nil
+          default_upload = Upload.find(-1)
 
-        expect(user_history.action).to eq(
-          UserHistory.actions[:change_site_setting]
-        )
+          put "/admin/site_settings/test_upload.json", params: {
+            test_upload: default_upload.url
+          }
 
-        expect(user_history.previous_value).to eq(nil)
-        expect(user_history.new_value).to eq(upload.url)
+          expect(response.status).to eq(200)
+          expect(SiteSetting.test_upload).to eq(default_upload)
+        end
 
-        put "/admin/site_settings/test_upload.json", params: {
-          test_upload: nil
-        }
+        it 'can update the site setting' do
+          upload = Fabricate(:upload)
 
-        expect(response.status).to eq(200)
-        expect(SiteSetting.test_upload).to eq(nil)
+          put "/admin/site_settings/test_upload.json", params: {
+            test_upload: upload.url
+          }
+
+          expect(response.status).to eq(200)
+          expect(SiteSetting.test_upload).to eq(upload)
+
+          user_history = UserHistory.last
+
+          expect(user_history.action).to eq(
+            UserHistory.actions[:change_site_setting]
+          )
+
+          expect(user_history.previous_value).to eq(nil)
+          expect(user_history.new_value).to eq(upload.url)
+        end
       end
 
       it 'logs the change' do