Fix minor bug redelivering to multiple

When passing multiple destinations as a CSV [1], we're expecting to
strip these values down to an Array of two stripped ID numbers [2].

This wasn't happening as the `each` call wasn't returning the stripped
values. As such, we're left with some invalid ID numbers [3] that don't
get found later on.

This fixes this issue by using `map`, which returns the stripped values.

I've also added some specs. They're not the totally complete, but they
do fail prior to using `map` and pass afterwards, so good enough for
this specific issue.

[1] e.g. `"105, 106"`
[2] i.e. `["105", "106"]`
[3] i.e. `["105", " 106"]` – note the preceding space

app/controllers/admin_incoming_message_controller.rb

@@ -78,7 +78,7 @@ def bulk_destroy
   end
 
   def redeliver
-    message_ids = params[:url_title].split(',').each(&:strip)
+    message_ids = params[:url_title].split(',').map(&:strip)
     previous_request = @incoming_message.info_request
     destination_request = nil
 

spec/controllers/admin_incoming_message_controller_spec.rb

@@ -74,6 +74,7 @@
       FactoryBot.create(:incoming_message, info_request: previous_info_request)
     end
     let(:destination_info_request) { FactoryBot.create(:info_request) }
+    let(:destination_info_request_2) { FactoryBot.create(:info_request) }
 
     it 'expires the file cache for the previous request' do
       allow(IncomingMessage).to receive(:find).and_return(incoming_message)
@@ -107,6 +108,29 @@
       expect(response).to redirect_to admin_request_url(incoming_message.info_request)
     end
 
+    context 'when redelivering to multiple requests' do
+      before do
+        destination_params =
+          [destination_info_request, destination_info_request_2].
+          map(&:id).
+          join(', ')
+
+        post :redeliver,
+             params: { id: incoming_message.id,
+                       url_title: destination_params }
+      end
+
+      it 'renders a message' do
+        msg = 'Message has been moved to request(s). Showing the last one:'
+        expect(flash[:notice]).to eq(msg)
+      end
+
+      it 'redirects to the last given destination request' do
+        expect(response).
+          to redirect_to admin_request_path(destination_info_request_2)
+      end
+    end
+
     context 'if the request is embargoed', feature: :alaveteli_pro do
       before do
         incoming_message.info_request.create_embargo