Do not exceed color range

test/spec/ol/render/canvas/hitdetect.test.js

@@ -0,0 +1,33 @@
+import {createHitDetectionImageData} from '../../../../../src/ol/render/canvas/hitdetect.js';
+import {create} from '../../../../../src/ol/transform.js';
+import Feature from '../../../../../src/ol/Feature.js';
+import Point from '../../../../../src/ol/geom/Point.js';
+import {Style} from '../../../../../src/ol/style.js';
+import Circle from '../../../../../src/ol/style/Circle.js';
+
+describe('hitdetect', function() {
+
+  let features, styleFunction;
+
+  beforeEach(function() {
+    features = [
+      new Feature(new Point([0, 75])),
+      new Feature(new Point([0, 50])),
+      new Feature(new Point([0, 25])),
+      new Feature(new Point([0, 0]))
+    ];
+    styleFunction = function() {
+      return new Style({
+        image: new Circle({
+          radius: 5
+        })
+      });
+    };
+  });
+
+  it ('does not exceed the color range', function() {
+    const imageData = createHitDetectionImageData([2, 2], [create()], features, styleFunction, [0, 0, 0, 0], 1, 0);
+    expect(Array.prototype.slice.call(imageData.data, 0, 3)).to.eql([255, 255, 252]);
+  });
+
+});