Add worker loader to the tests

test/karma.config.js

@@ -86,6 +86,14 @@ module.exports = function(karma) {
             },
             include: path.resolve('src/ol/'),
             exclude: path.resolve('node_modules/')
+          }, {
+            test: /\.js$/,
+            use: {
+              loader: path.join(__dirname, '../examples/webpack/worker-loader.js')
+            },
+            include: [
+              path.join(__dirname, '../src/ol/worker')
+            ]
           }
         ]
       }

test/spec/ol/worker/version.test.js

@@ -0,0 +1,32 @@
+import {create} from '../../../../src/ol/worker/version.js';
+import {VERSION} from '../../../../src/ol/util.js';
+
+
+describe('ol/worker/version', function() {
+
+  let worker;
+  beforeEach(function() {
+    worker = create();
+  });
+
+  afterEach(function() {
+    if (worker) {
+      worker.terminate();
+    }
+    worker = null;
+  });
+
+  describe('messaging', function() {
+    it('responds with the version', function(done) {
+      worker.addEventListener('error', done);
+
+      worker.addEventListener('message', function(event) {
+        expect(event.data).to.equal('version: ' + VERSION);
+        done();
+      });
+
+      worker.postMessage('test message');
+    });
+  });
+
+});