Prevent calling UAA twice when creating new user through /v3/users

app/controllers/v3/users_controller.rb

@@ -47,7 +47,13 @@ def create
 
     user = UserCreate.new.create(message:)
 
-    render status: :created, json: Presenters::V3::UserPresenter.new(user, uaa_users: User.uaa_users_info([user.guid]))
+    if message.username && message.origin
+      render status: :created,
+             json: Presenters::V3::UserPresenter.new(user,
+                                                     uaa_users: { user.guid => { 'username' => message.username, 'id' => user.guid, 'origin' => message.origin } })
+    else
+      render status: :created, json: Presenters::V3::UserPresenter.new(user, uaa_users: User.uaa_users_info([user.guid]))
+    end
   rescue VCAP::CloudController::UaaUnavailable
     raise CloudController::Errors::ApiError.new_from_details('UaaUnavailable')
   rescue UserCreate::Error => e

spec/request/users_spec.rb

@@ -905,18 +905,19 @@
         end
 
         before do
-          allow(uaa_client).to receive(:users_for_ids).with(['new-user-guid']).and_return(
-            {
-              user_guid => {
-                'username' => 'some-user',
-                'origin' => 'idp.local'
-              }
-            }
-          )
           allow(uaa_client).to receive(:create_shadow_user).and_return({ 'id' => user_guid })
         end
 
         it_behaves_like 'permissions for single object endpoint', ALL_PERMISSIONS
+
+        it 'constructs the response with the given information without calling the UAA again' do
+          post '/v3/users', params.to_json, admin_header
+
+          expect(last_response).to have_status_code(201)
+          expect(parsed_response).to match_json_response(user_json)
+
+          expect(uaa_client).not_to have_received(:users_for_ids)
+        end
       end
 
       context 'when parameters are invalid' do