Show error when Jira did not return any projects

app/controllers/projects/import/jira_controller.rb

@@ -9,7 +9,13 @@ module Projects
       def show
         unless @project.import_state&.in_progress?
           jira_client = @project.jira_service.client
-          @jira_projects = jira_client.Project.all.map { |p| ["#{p.name} (#{p.key})", p.key] }
+          jira_projects = jira_client.Project.all
+
+          if jira_projects.present?
+            @jira_projects = jira_projects.map { |p| ["#{p.name} (#{p.key})", p.key] }
+          else
+            flash[:alert] = 'No projects have been returned from Jira. Please check your Jira configuration.'
+          end
         end
 
         flash[:notice] = _("Import %{status}") % { status: @project.import_state.status } if @project.import_state.present? && !@project.import_state.none?

app/views/projects/import/jira/show.html.haml

@@ -9,7 +9,7 @@
   %h3.page-title.d-flex.align-items-center
     = sprite_icon('issues', size: 16, css_class: 'mr-1')
     = _('Import in progress')
-- else
+- elsif @jira_projects.present?
   %h3.page-title.d-flex.align-items-center
     = sprite_icon('issues', size: 16, css_class: 'mr-1')
     = _('Import issues from Jira')

spec/controllers/projects/import/jira_controller_spec.rb

@@ -66,13 +66,29 @@ describe Projects::Import::JiraController do
 
         context 'when running jira import first time' do
           context 'get show' do
-            it 'renders show template' do
-              allow(JIRA::Resource::Project).to receive(:all).and_return([])
+            before do
+              allow(JIRA::Resource::Project).to receive(:all).and_return(jira_projects)
+
               expect(project.import_state).to be_nil
 
               get :show, params: { namespace_id: project.namespace.to_param, project_id: project }
+            end
+
+            context 'when no projects have been retrieved from Jira' do
+              let(:jira_projects) { [] }
+
+              it 'render an error message' do
+                expect(flash[:alert]).to eq('No projects have been returned from Jira. Please check your Jira configuration.')
+                expect(response).to render_template(:show)
+              end
+            end
+
+            context 'when everything is ok' do
+              let(:jira_projects) { [double(name: 'FOO project', key: 'FOO')] }
 
-              expect(response).to render_template :show
+              it 'renders show template' do
+                expect(response).to render_template(:show)
+              end
             end
           end