Nodemailer-stub comes with a stub transport for Nodemailer. The Stub stores the messages in memory but mimics real mail behaviour. It also contains a smart testing class called InteractsWithMail, which allows users to access, read, count and flush the messages in memory in their testing environment.

$ yarn add nodemailer-stub -D
#... or via npm
$ npm install nodemailer-stub --save-dev

This is an example use case for the Stub.

import { stubTransport } from 'nodemailer-stub'
import nodeMailer from 'nodemailer'

let transport = nodeMailer.createTransport(stubTransport)

let mail = await transport.sendMail({
  from: 'john.doe@domain.com',
  to: 'jim@otherdomain.com',
  subject: 'Nodemailer stub works!',
  text: 'Wohoo'
})

For testing purposes, there is also a transport called errorTransport, where the transport throws an error during execution, to help with testing the robustness of your mail service logic.

We've also included a testing utility class, called interactsWithMail. You can use it in your tests like this:

import { interactsWithMail as iwm } from 'nodemailer-stub'

const exampleMail = {
  to: 'john@domain.com',
  from: 'jimmy@domain.com',
  subject: 'testing',
  content: 'foo',
  contents: ['foo'],
  contentType: 'text/plain'
}

test('it retrieves the last message', () => {
  iwm.newMail(exampleMail)

  let lastMail = iwm.lastMail()

  lastMail.to.should.eq('john@domain.com')
  lastMail.from.should.eq('jimmy@domain.com')
  lastMail.subject.should.eq('testing')
  lastMail.content.should.eq(['foo'])
  lastMail.contents.should.eq(['foo'])
  lastMail.contentType.should.eq('text/plain')
})

Available methods for interactsWithMail:

Retrieves last mail. Accessible properties:

• from
• to
• subject
• content
• contents
• contentType

Adds a new mail to the list of all mails.

Available properties:

• from (required)
• to (required)
• subject
• text (required)

Flushes all messages. Useful when testing multiple occurrences of mailer, and should be used in afterAll or afterEach hooks in your tests.

Retrieves a count of how many emails were sent in the last mailer call.

All tests can be executed with the following command:

$ yarn test

See LICENSE file.