Add back in plugin mock

Author: danbovey

test/indexTest.js

@@ -17,6 +17,7 @@ describe("Port function",function(){
   });
 
   it("Port value should be >= 0 and < 65536",function(done){
+    let service = new Plugin(serverlessMock, {});
     http.get(`http://localhost:${service.port}/shell/`, function (response) {
       assert.equal(response.statusCode, 200);
       done();