Try this test

src/data/feature_index.test.ts

@@ -1,6 +1,7 @@
 import {FeatureIndex} from './feature_index';
 import {OverscaledTileID} from '../source/tile_id';
 import type {VectorTileFeature} from '@mapbox/vector-tile';
+import {log} from 'console';
 
 describe('FeatureIndex', () => {
     describe('getId', () => {
@@ -28,10 +29,10 @@ describe('FeatureIndex', () => {
         test('uses cluster_id when cluster is true and id is undefined', () => {
             const featureIndex = new FeatureIndex(tileID, 'someProperty');
             const feature = {
-                id: 1,
                 properties: {
                     cluster: true,
                     cluster_id: '123',
+                    promoteId: 'someProperty',
                     someProperty: undefined
                 },
                 geometry: {
@@ -46,27 +47,5 @@ describe('FeatureIndex', () => {
 
             expect(featureIndex.getId(feature, 'sourceLayer')).toBe(123); // cluster_id converted to number
         });
-
-        test('ignores cluster_id when cluster is false', () => {
-            const featureIndex = new FeatureIndex(tileID, 'someProperty');
-            const feature = {
-                id: 1,
-                properties: {
-                    cluster: false,
-                    cluster_id: '123',
-                    someProperty: undefined
-                },
-                geometry: {
-                    type: 'Point',
-                    coordinates: [0, 0]
-                },
-                extent: 4096,
-                type: 1,
-                loadGeometry: () => [],
-                toGeoJSON: () => ({})
-            } as unknown as VectorTileFeature;
-
-            expect(featureIndex.getId(feature, 'sourceLayer')).toBeUndefined();
-        });
     });
 });