Add rendering test for multipoint with icon and text

rendering/cases/layer-vector-multipoint-decluttering/main.js

@@ -0,0 +1,53 @@
+import Feature from '../../../src/ol/Feature.js';
+import Map from '../../../src/ol/Map.js';
+import MultiPoint from '../../../src/ol/geom/MultiPoint.js';
+import VectorSource from '../../../src/ol/source/Vector.js';
+import View from '../../../src/ol/View.js';
+import {Icon, Stroke, Style, Text} from '../../../src/ol/style.js';
+import {Vector as VectorLayer} from '../../../src/ol/layer.js';
+
+const vectorLayer = new VectorLayer({
+  declutter: true,
+  renderBuffer: 0,
+  source: new VectorSource({
+    features: [
+      new Feature(
+        new MultiPoint([
+          [0, 0],
+          [0, 1],
+          [0.5, 0.5],
+          [0.9, 0.85],
+          [1, 0],
+          [0.3, 0.5],
+        ])
+      ),
+    ],
+  }),
+  style: new Style({
+    image: new Icon({
+      anchor: [0.5, 46],
+      anchorXUnits: 'fraction',
+      anchorYUnits: 'pixels',
+      src: '/data/icon.png',
+    }),
+    text: new Text({
+      text: 'Test',
+      font: '700 italic 20px "Quattrocento Sans"',
+      stroke: new Stroke({
+        color: 'red',
+        width: 20,
+      }),
+    }),
+  }),
+});
+
+new Map({
+  layers: [vectorLayer],
+  target: document.getElementById('map'),
+  view: new View({
+    center: [0.5, 0.5],
+    resolution: 0.006679631467570084,
+  }),
+});
+
+render({tolerance: 0.007});