1 files changed, 31 insertions, 1 deletions
diff --git a/spec/models/members/group_member_spec.rb b/spec/models/members/group_member_spec.rb
index 9b5cce1aebf..fdb71b7ec7d 100644
--- a/spec/models/members/group_member_spec.rb
+++ b/spec/models/members/group_member_spec.rb
@@ -4,7 +4,7 @@ require 'spec_helper'
 
 describe GroupMember do
   context 'scopes' do
-    describe '.count_users_by_group_id' do
+    shared_examples '.count_users_by_group_id' do
       it 'counts users by group ID' do
         user_1 = create(:user)
         user_2 = create(:user)
@@ -20,6 +20,36 @@ describe GroupMember do
       end
     end
 
+    describe '.count_users_by_group_id with optimized_count_users_by_group_id feature flag on' do
+      before do
+        stub_feature_flags(optimized_count_users_by_group_id: true)
+      end
+
+      it_behaves_like '.count_users_by_group_id'
+
+      it 'does not JOIN users' do
+        scope = described_class.all
+        expect(scope).not_to receive(:joins).with(:user)
+
+        scope.count_users_by_group_id
+      end
+    end
+
+    describe '.count_users_by_group_id with optimized_count_users_by_group_id feature flag off' do
+      before do
+        stub_feature_flags(optimized_count_users_by_group_id: false)
+      end
+
+      it_behaves_like '.count_users_by_group_id'
+
+      it 'does JOIN users' do
+        scope = described_class.all
+        expect(scope).to receive(:joins).with(:user).and_call_original
+
+        scope.count_users_by_group_id
+      end
+    end
+
     describe '.of_ldap_type' do
       it 'returns ldap type users' do
         group_member = create(:group_member, :ldap)