Update test that relies on ES5-style classes

Author: confused-Techie

spec/disposable-spec.js

@@ -23,19 +23,18 @@ describe("Disposable", function() {
     expect(disposalAction.callCount).toBe(1)
   })
 
-  it('can be extended by ES5-style classes', () => {
-    function MyDisposable () {
-      // super
-      Disposable.apply(this, arguments)
+  it("can be extended by ES6-style classes", () => {
+    class MyDisposable extends Disposable {
+      constructor(...args) {
+        super(...args);
+      }
     }
 
-    MyDisposable.prototype = new Disposable()
-
-    let actionCalled = false
-    const disposable = new MyDisposable(() => { actionCalled = true })
-    disposable.dispose()
-    expect(actionCalled).toBe(true)
-  })
+    let actionCalled = false;
+    const disposable = new MyDisposable(() => { actionCalled = true });
+    disposable.dispose();
+    expect(actionCalled).toBe(true);
+  });
 
   describe(".isDisposable(object)", () => {
     it("true if the object implements the ::dispose function", function() {