test(testSchedulerUi): do not convert synchronous test to async test

spec/Observable-spec.ts

@@ -1,4 +1,5 @@
 import {expect} from 'chai';
+import * as sinon from 'sinon';
 import * as Rx from '../dist/cjs/Rx';
 import {TeardownLogic} from '../dist/cjs/Subscription';
 
@@ -211,6 +212,9 @@ describe('Observable', () => {
     });
 
     it('should run unsubscription logic when an error is sent asynchronously and subscribe is called with no arguments', (done: MochaDone) => {
+      const sandbox = sinon.sandbox.create();
+      const fakeTimer = sandbox.useFakeTimers();
+
       let unsubscribeCalled = false;
       const source = new Observable((subscriber: Rx.Subscriber<string>) => {
         const id = setInterval(() => {
@@ -244,6 +248,9 @@ describe('Observable', () => {
           }
         }
       }, 100);
+
+      fakeTimer.tick(110);
+      sandbox.restore();
     });
 
     it('should return a Subscription that calls the unsubscribe function returned by the subscriber', () => {

spec/helpers/testScheduler-ui.ts

@@ -155,7 +155,7 @@ module.exports = function(suite) {
       let modified = fn;
 
       if (fn && fn.length === 0) {
-        modified = function (done: MochaDone) {
+        modified = function () {
           context.rxTestScheduler = new Rx.TestScheduler(observableMatcher);
           let error: Error = null;
 
@@ -166,7 +166,6 @@ module.exports = function(suite) {
             error = e instanceof Error ? e : new Error(e);
           } finally {
             context.rxTestScheduler = null;
-            error ? done(error) : done();
           }
         };
       }

spec/subjects/BehaviorSubject-spec.ts

@@ -8,10 +8,9 @@ const ObjectUnsubscribedError = Rx.ObjectUnsubscribedError;
 
 /** @test {BehaviorSubject} */
 describe('BehaviorSubject', () => {
-  it('should extend Subject', (done: MochaDone) => {
+  it('should extend Subject', () => {
     const subject = new BehaviorSubject(null);
     expect(subject instanceof Rx.Subject).to.be.true;
-    done();
   });
 
   it('should throw if it has received an error and getValue() is called', () => {