Replaces clip.test.js with new tests

Transforms the old rendering test for
layer clipping to the new rendering test approach.

rendering/cases/layer-clipping/main.js

@@ -0,0 +1,61 @@
+import Map from '../../../src/ol/Map.js';
+import View from '../../../src/ol/View.js';
+import XYZ from '../../../src/ol/source/XYZ.js';
+import TileLayer from '../../../src/ol/layer/Tile.js';
+import MultiPolygon from '../../../src/ol/geom/MultiPolygon.js';
+import Style from '../../../src/ol/style/Style.js';
+import Stroke from '../../../src/ol/style/Stroke.js';
+import {getVectorContext} from '../../../src/ol/render.js';
+
+const source = new XYZ({
+  url: '/data/tiles/osm/{z}/{x}/{y}.png',
+  transition: 0
+});
+
+const layer = new TileLayer({
+  source: source
+});
+
+const geometry = new MultiPolygon([
+  [[[-80, -40], [-40, 0], [-80, 40], [-120, 0], [-80, -40]]],
+  [[[80, -40], [120, 0], [80, 40], [40, 0], [80, -40]]]
+]).transform('EPSG:4326', 'EPSG:3857');
+
+const style = new Style({
+  stroke: new Stroke({
+    width: 2,
+    color: 'blue'
+  })
+});
+
+layer.on('prerender', function(event) {
+  const context = event.context;
+  context.save();
+
+  const vectorContext = getVectorContext(event);
+  vectorContext.setStyle(style);
+  vectorContext.drawGeometry(geometry);
+
+  context.clip();
+});
+
+layer.on('postrender', function(event) {
+  const context = event.context;
+  context.restore();
+
+  const vectorContext = getVectorContext(event);
+  vectorContext.setStyle(style);
+  vectorContext.drawGeometry(geometry);
+});
+
+new Map({
+  pixelRatio: 1,
+  target: 'map',
+  layers: [layer],
+  view: new View({
+    center: [0, 0],
+    zoom: 0
+  })
+});
+
+render();