test: add concurrent sync regression test for LDAP team sync

Signed-off-by: Mohit25022005 <mohitswarnkar13@gmail.com>

services/auth/source/oauth2/source_group_sync_test.go

@@ -0,0 +1,57 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package oauth2
+
+import (
+	"sync"
+	"testing"
+
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/organization"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/container"
+	auth_source "code.gitea.io/gitea/services/auth/source"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSyncGroupsToTeamsConcurrentRuns(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	ctx := t.Context()
+	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 4})
+	team := unittest.AssertExistsAndLoadBean(t, &organization.Team{ID: 2})
+	org := unittest.AssertExistsAndLoadBean(t, &organization.Organization{ID: team.OrgID})
+
+	sourceGroupTeamMapping := map[string]map[string][]string{
+		"ldap-group": {
+			org.Name: []string{team.Name},
+		},
+	}
+
+	var wg sync.WaitGroup
+	for i := 0; i < 10; i++ {
+		wg.Add(2)
+		go func() {
+			defer wg.Done()
+			assert.NoError(t, auth_source.SyncGroupsToTeams(ctx, user, container.SetOf("ldap-group"), sourceGroupTeamMapping, true))
+		}()
+		go func() {
+			defer wg.Done()
+			assert.NoError(t, auth_source.SyncGroupsToTeams(ctx, user, container.Set[string]{}, sourceGroupTeamMapping, true))
+		}()
+	}
+	wg.Wait()
+
+	memberCount, err := db.GetEngine(ctx).Count(&organization.TeamUser{OrgID: team.OrgID, TeamID: team.ID, UID: user.ID})
+	assert.NoError(t, err)
+	assert.LessOrEqual(t, memberCount, int64(1))
+
+	team = unittest.AssertExistsAndLoadBean(t, &organization.Team{ID: team.ID})
+	totalCount, err := db.GetEngine(ctx).Count(&organization.TeamUser{OrgID: team.OrgID, TeamID: team.ID})
+	assert.NoError(t, err)
+	assert.EqualValues(t, team.NumMembers, totalCount)
+	assert.GreaterOrEqual(t, team.NumMembers, 0)
+}