mocha error "unhandled rejection ValidationError: Path `name` is required"

Testing in nodejs project is new for me. I have testing for segment models, when run gulp test then it show error.

Here code,

//segment.model.js

'use strict';

import crypto from 'crypto';
var mongoose = require('bluebird').promisifyAll(require('mongoose'));
import { Schema } from 'mongoose';

var SegmentSchema = new Schema({
    name: {type:String,required: true},
    attribute: [{
        name: String,
        uiName: String,
        type: { type: String },
        value: String,
        min: Number,
        max:Number,
        status:Boolean
    }],
    createdBy: {
        type: Schema.Types.ObjectId,
        ref: 'User',
        required:true
    },

});



SegmentSchema.methods={

    checkAttributeLength(attribute){
        return (attribute.length > 0)?true:false;
    }
}
export default mongoose.model('Segment', SegmentSchema);

Testing File:

//segment.model.spec.js   

'use strict';
import app from '../..';
import Segment from './segment.model';
import mongoose from 'mongoose';
// var mongoose = require('mongoose');

var Schema = mongoose.Schema,
    ObjectId = Schema.ObjectId;
var segment;
var getSegment = function() {
    segment = new Segment({
        "name": "Segment 34312",
        "createdBy": "56f8ff4a769fae4f7f88c456",
        "attribute": [{
            "name": "city",
            "uiName": "City",
            "type": "text",
            "value": "NEWJERSY",
        }, {
            "name": "zip",
            "uiName": "Zip code",
            "type": "text",
            "value": "123456",
        }, {
            "name": "number_of_children",
            "uiName": "No. of children",
            "type": "range",
            "min": 12,
            "max": 14,
        }, {
            "name": "pets_dog",
            "uiName": "Dog owner",
            "type": "binary",
            "status": true,
        }, {
            "name": "financial",
            "uiName": "MO: financial",
            "type": "select",
            "value": "M",
        }],
    });
    return segment;
};

describe('Segment Model', function() {

    before(function() {
        // Clear users before testing
        return Segment.removeAsync();
    });

    beforeEach(function() {
        getSegment();
    });

    afterEach(function() {
        return Segment.removeAsync();
    });

    it('should begin with no segments', function() {
        return expect(Segment.findAsync({})).to
            .eventually.have.length(0);
    });

    describe('#segment_name', function() {
        it('should fail when saving with blank segment name', function() {
            segment.name = '';
            return expect(segment.saveAsync()).to.be.rejected;
        });
    });
    describe('#segment_createdBy', function() {
        it('should fail when saving without user id which created segment', function() {
            segment.createdBy ='';
            return expect(segment.saveAsync()).to.be.rejected;
        });
    });

    describe('#segment_attribute', function() {
        it('should fail when attribute length is zero', function() {
            segment.attribute=[];
            return expect(segment.checkAttributeLength(segment.attribute)).to.be.false;
        });
    });

});

Error:

..... ..... #segment_name

✓ should fail when saving with blank segment name Unhandled rejection ValidationError: Path name is required. at MongooseError.ValidationError (/home/chotelal/nrich/node_modules/mongoose/lib/error/validation.js:22:11) at model.Document.invalidate (/home/chotelal/nrich/node_modules/mongoose/lib/document.js:1338:32) at /home/chotelal/nrich/node_modules/mongoose/lib/document.js:1206:17 at validate (/home/chotelal/nrich/node_modules/mongoose/lib/schematype.js:693:7) at /home/chotelal/nrich/node_modules/mongoose/lib/schematype.js:724:9 at Array.forEach (native) at SchemaString.SchemaType.doValidate (/home/chotelal/nrich/node_modules/mongoose/lib/schematype.js:698:19) at /home/chotelal/nrich/node_modules/mongoose/lib/document.js:1204:9 at _combinedTickCallback (node.js:376:9) at process._tickDomainCallback (node.js:431:11) ..... ....