mongo-unit

This library is done to simplify creation of integration tests for node.js application with Mongo DB.
I starts local mongodb process using mongodb-memory-server library,
and it work in "InMemory" mode, which improve performance of your tests.

$3

Since running embedded mongo takes some time, we need to config mocha to wait until mongo is up and running, the easiest way to do it add --delay flag for mocha and handle async flow, like this

``
//package.json
...
"scripts": {
...
"test": "mocha ./*/.spec.js --delay",
...
},
...
`

add init.spec.js

`javascript
//init.spec.js
const mongoUnit = require('mongo-unit')

mongoUnit.start().then(() => {
console.log('fake mongo is started: ', mongoUnit.getUrl())
process.env.DATABASE_URL = mongoUnit.getUrl() // this var process.env.DATABASE_URL = will keep link to fake mongo
run() // this line start mocha tests
})

after(() => {
const dao = require('./dao')
console.log('stop')
dao.close()
return mongoUnit.stop()
})
`

Code under test
`javascript
//dao.js
const mongoose = require('mongoose')

const userSchema = new mongoose.Schema({
name: String,
})
const taskSchema = new mongoose.Schema({
userId: String,
task: String,
})

module.exports = {
init: () => mongoose.connect(process.env.DATABASE_URL),
close: () => mongoose.disconnect(),
User: mongoose.model('user', userSchema),
Task: mongoose.model('task', taskSchema),
}
`
Test data
`json
{
"users": [
{
"_id": "56d9bf92f9be48771d6fe5b1",
"name": "test"
},
{
"_id": "56d9bf92f9be48771d6fe5b2",
"name": "John"
}
],
"tasks": [
{
"userId": "56d9bf92f9be48771d6fe5b1",
"task": "do stuff"
},
{
"userId": "56d9bf92f9be48771d6fe5b1",
"task": "fix stuff"
}
]
}
`
Mocha test
`javascript
//dao.spec.js
const {expect} = require('chai')
const mongoUnit = require('mongo-unit')
const testData = require('./data.json')
const daoUT = require('./dao')
describe('dao', ()=>{

before(() => daoUT.init())
beforeEach(() => mongoUnit.load(testData))
afterEach(() => mongoUnit.drop())

it('should find all users', () => {
return daoUT.User.find()
.then(users => {
expect(users.length).to.equal(2)
expect(users[0].name).to.equal('test')
})
})

it('should find all tasks for user 1', () => {
return daoUT.User.find()
.then(users => users[0])
.then(user=>daoUT.Task.find({userId: user._id}))
.then(tasks => {
expect(tasks.length).to.equal(2)
expect(tasks[0].task).to.equal('do stuff')
})
})
})
`

General info


I was inspired by dbUnit library, which is very popular in java world.

> There is alternative library for mocking Mongo: mockgoose

Requirements

It works on Node.js 12+

Installation

npm install -D mongo-unit

Run test in docker example

docker build -t mongo-unit .
docker run -it mongo-unit

API

$3

It starts mongod on one of available port and returns Promise with URL to connect to this db.
opts is optional params, you can specify some command line params for mongod:

* opts.port - preferable mongo db port, default: 27017
* opts.dbName - name of test db, default: test
* opts.dbpath - db path, default: \.mongo-unit
* opts.verbose - enable debug logs, default: false
* opts.version - specify which version of mongo to download. e.g. version=v3.6
* opts.useReplicateSet - specify we want to start the memory server as a MongoMemoryReplSet needed to support transactions, default: false
* opts.storageEngine - specify the Mongo storage engine to use (e.g., wiredTiger); default: non-replica set ephemeralForTest, replica set wiredTiger. (Note that as of Mongo 7+, ephemeralForTest is no longer supported or allowed, so you will have to specify an option here.)

mongodb-memory-server can also be configured via environment variables.
For instance, export MONGOMS_DEBUG=1will activate debug logging in the memory server. See their docs for more information.




$3

It stops mongod process

$3

Syncronius API returns URL to connect to test db, if test DB is not started it thows an Exception

$3

Inserts given data (like below) DB collections, returns Promise.

`json
{
"collectionName1":[
{"field1":"value1"},
{"field2":"value2"}
],
"collectionName2":[
{"field3":"value3"},
{"field4":"value4"}
]
}
``

$3

Clear collections based on given data (data format is the same), returns Promise.

$3

Drops test DB, returns Promise.

$3

helper function, load db data into mongo

$3

helper function, clear all db data from mongo