How to do an index search in Mongoose?

Question

Node.js

You need to do a full-text search on the table (mongoDB).
Went to off documentation.
Here is the diagram:

var mongoose = require('mongoose');

var testSchema = new mongoose.Schema({
  tags: [],
  text: { type: String }
});

testSchema.index({text: 'text', tags: 'text'});
module.exports = mongoose.model('Test', testSchema);

Search code:

var test = require('../models/Test.js');

  test
    .find({ $text : { $search : "random" } })
    .exec(function(err, results) {
      if (err) return res.send(err);
      res.send(results)
    });

Objects from the base:

{ 
    "_id" : ObjectId("57f3d21358b045bc1f16a156"), 
    "text" : "random 1", 
    "tags" : [ "a", "b", "c" ]
}
{ 
    "_id" : ObjectId("57f3d2a858b045bc1f16a157"), 
    "text" : "test str 2", 
    "tags" : [ "d",   "e",  "f" ]
}
{ 
    "_id" : ObjectId("57f3d2b758b045bc1f16a158"), 
    "text" : "random 2", 
    "tags" : [ "a",  "e",  "f" ]
}

The problem is that the result comes: an empty array []
Tell me where I made a mistake or throw off an example of a working code, if any. (you can’t use elastic or sphinx so they said to do it on mong)