diff --git a/backend/internal/autoassignment/capacity_test.go b/backend/internal/autoassignment/capacity_test.go
index ad350f6f..ea2f1db1 100644
--- a/backend/internal/autoassignment/capacity_test.go
+++ b/backend/internal/autoassignment/capacity_test.go
@@ -214,7 +214,11 @@ func TestAssignmentEligibilityRejectsSoftDeletedUserAndAccountUser(t *testing.T)
 }
 
 func TestLongestWaitingSortsUnknownActivityLast(t *testing.T) {
-	db := setupCapacityAssignmentDB(t)
+	testLongestWaitingSortsUnknownActivityLast(t, setupCapacityAssignmentDB(t))
+}
+
+func testLongestWaitingSortsUnknownActivityLast(t *testing.T, db *gorm.DB) {
+	t.Helper()
 	account := &model.Account{Name: "Longest waiting"}
 	require.NoError(t, db.Create(account).Error)
 	inbox := &model.Inbox{AccountID: account.ID, Name: "Inbox", ChannelType: string(model.InboxChannelTypeWebWidget)}
diff --git a/backend/internal/autoassignment/coverage9_test.go b/backend/internal/autoassignment/coverage9_test.go
index 65cc81fb..e3b9a0a7 100644
--- a/backend/internal/autoassignment/coverage9_test.go
+++ b/backend/internal/autoassignment/coverage9_test.go
@@ -221,6 +221,14 @@ func TestAssignmentServiceOnlyOneConcurrentWorkerWinsPostgres(t *testing.T) {
 	testAssignmentServiceOnlyOneConcurrentWorkerWins(t, db, rdb)
 }
 
+func TestLongestWaitingSortsUnknownActivityLastPostgres(t *testing.T) {
+	if os.Getenv("GOCHAT_TEST_DB") != "postgres" {
+		t.Skip("PostgreSQL longest-waiting test")
+	}
+	db, _ := setupFullAAPostgresDB_Cov9(t)
+	testLongestWaitingSortsUnknownActivityLast(t, db)
+}
+
 func testAssignmentServiceOnlyOneConcurrentWorkerWins(t *testing.T, db *gorm.DB, rdb *redis.Client) {
 	t.Helper()
 	account, agent, inbox, conversation := seedAssignableConversation_Cov9(t, db)