improve test

Author: bytestream

tests/echo.test.ts

@@ -1,5 +1,5 @@
 import Echo from '../src/echo';
-import {PusherConnector} from "../src/connector";
+import {NullConnector, PusherConnector} from "../src/connector";
 
 describe('Echo', () => {
     test('it will not throw error for supported driver', () => {
@@ -11,15 +11,12 @@ describe('Echo', () => {
             'Broadcaster string pusher is not supported.'
         );
 
-        expect(() => new Echo({ broadcaster: PusherConnector })).not.toThrowError(
-            'Broadcaster string pusher is not supported.'
-        );
-
         expect(() => new Echo({ broadcaster: 'socket.io' })).not.toThrowError(
             'Broadcaster string socket.io is not supported.'
         );
 
         expect(() => new Echo({ broadcaster: 'null' })).not.toThrowError('Broadcaster string null is not supported.');
+        expect(() => new Echo({ broadcaster: NullConnector })).not.toThrowError();
 
         // eslint-disable-next-line
         // @ts-ignore