Address minor backend comments

Moves a common test to a shared example
block for re-use

app/assets/javascripts/projects/settings/init_transfer_project_form.js

@@ -39,7 +39,7 @@ export default () => {
         },
         on: {
           selectNamespace: (id) => {
-            if (targetHiddenInputId && document.getElementById(targetHiddenInputId)?.value) {
+            if (targetHiddenInputId && document.getElementById(targetHiddenInputId)) {
               document.getElementById(targetHiddenInputId).value = id;
             }
           },

app/helpers/namespaces_helper.rb

@@ -90,7 +90,7 @@ module NamespacesHelper
 
   def namespaces_as_json(selected = :current_user)
     {
-      group: formatted_namespaces(current_user.manageable_groups_with_routes),
+      group: formatted_namespaces(current_user.manageable_groups_with_routes(include_groups_with_developer_maintainer_access: true)),
       user: formatted_namespaces([current_user.namespace])
     }.to_json
   end

spec/controllers/projects_controller_spec.rb

@@ -904,24 +904,7 @@ RSpec.describe ProjectsController do
     let_it_be(:admin) { create(:admin) }
     let_it_be(:new_namespace) { create(:namespace) }
 
-    it 'updates namespace' do
-      sign_in(admin)
-
-      put :transfer,
-          params: {
-            namespace_id: project.namespace.path,
-            new_namespace_id: new_namespace.id,
-            id: project.path
-          },
-          format: :js
-
-      project.reload
-
-      expect(project.namespace).to eq(new_namespace)
-      expect(response).to have_gitlab_http_status(:ok)
-    end
-
-    context 'when new namespace is empty' do
+    shared_examples 'project namespace is not changed' do |flash_message|
       it 'project namespace is not changed' do
         controller.instance_variable_set(:@project, project)
         sign_in(admin)
@@ -931,7 +914,7 @@ RSpec.describe ProjectsController do
         put :transfer,
             params: {
               namespace_id: old_namespace.path,
-              new_namespace_id: nil,
+              new_namespace_id: new_namespace_id,
               id: project.path
             },
             format: :js
@@ -940,31 +923,37 @@ RSpec.describe ProjectsController do
 
         expect(project.namespace).to eq(old_namespace)
         expect(response).to redirect_to(edit_project_path(project))
-        expect(flash[:alert]).to eq s_('TransferProject|Please select a new namespace for your project.')
+        expect(flash[:alert]).to eq flash_message
       end
     end
 
-    context 'when new namespace is the same as the current namespace' do
-      it 'project namespace is not changed' do
-        controller.instance_variable_set(:@project, project)
-        sign_in(admin)
+    it 'updates namespace' do
+      sign_in(admin)
 
-        old_namespace = project.namespace
+      put :transfer,
+          params: {
+            namespace_id: project.namespace.path,
+            new_namespace_id: new_namespace.id,
+            id: project.path
+          },
+          format: :js
 
-        put :transfer,
-            params: {
-              namespace_id: project.namespace.path,
-              new_namespace_id: old_namespace.id,
-              id: project.path
-            },
-            format: :js
+      project.reload
 
-        project.reload
+      expect(project.namespace).to eq(new_namespace)
+      expect(response).to have_gitlab_http_status(:ok)
+    end
 
-        expect(project.namespace).to eq(old_namespace)
-        expect(response).to redirect_to(edit_project_path(project))
-        expect(flash[:alert]).to eq s_('TransferProject|Project is already in this namespace.')
-      end
+    context 'when new namespace is empty' do
+      let(:new_namespace_id) { nil }
+
+      it_behaves_like 'project namespace is not changed', s_('TransferProject|Please select a new namespace for your project.')
+    end
+
+    context 'when new namespace is the same as the current namespace' do
+      let(:new_namespace_id) { project.namespace.id }
+
+      it_behaves_like 'project namespace is not changed', s_('TransferProject|Project is already in this namespace.')
     end
   end