Gracefully handle adding of no users to projects and groups

- Disable {project, group} members submit button if no users

  If no users are selected, the submit button should be disabled.

- Alert user when no users were added to {project, group}.

  When no users were selected for adding, an alert message is
  flashed that no users were added.

- Also, this commit adds a feedback when users were actually added to a
  project, in symmetry with how group members are handled.

Closes #22967, #23270.

1 files changed, 54 insertions, 0 deletions

diff --git a/spec/controllers/groups/group_members_controller_spec.rb b/spec/controllers/groups/group_members_controller_spec.rb
index ad15b3f8f40..82eebe6f2d4 100644
--- a/spec/controllers/groups/group_members_controller_spec.rb
+++ b/spec/controllers/groups/group_members_controller_spec.rb
@@ -13,6 +13,60 @@ describe Groups::GroupMembersController do
     end
   end
 
+  describe '#create' do
+    let(:group) { create(:group, :public) }
+
+    context 'when users are added' do
+      let(:user) { create(:user) }
+      let(:group_user) { create(:user) }
+      let(:member) do
+        group.add_developer(group_user)
+        group.members.find_by(user_id: group_user)
+      end
+
+      context 'when user does not have enough rights' do
+        before do
+          group.members.delete(member)
+          group.add_developer(user)
+          sign_in(user)
+        end
+
+        it 'returns 403' do
+          post :create, group_id: group,
+                        user_ids: member
+
+          expect(response).to have_http_status(403)
+          expect(group.users).not_to include group_user
+        end
+      end
+
+      context 'when user has enough rights' do
+        before do
+          group.add_owner(user)
+          sign_in(user)
+        end
+
+        it 'adds user to members' do
+          post :create, group_id: group,
+                        user_ids: member
+
+          expect(response).to set_flash.to 'Users were successfully added.'
+          expect(response).to redirect_to(group_group_members_path(group))
+          expect(group.users).to include group_user
+        end
+
+        it 'adds no user to members' do
+          post :create, group_id: group,
+                        user_ids: ''
+
+          expect(response).to set_flash.to 'No users specified.'
+          expect(response).to redirect_to(group_group_members_path(group))
+          expect(group.users).not_to include group_user
+        end
+      end
+    end
+  end
+
   describe 'DELETE destroy' do
     let(:member) { create(:group_member, :developer, group: group) }