Fastify CLI decorators undefined - node.js

Question

I'm using fastify-cli for building my server application.
For testing I want to generate some test JWTs. Therefore I want to use the sign method of the fastify-jwt plugin.
If I run the application with fastify start -l info ./src/app.js everything works as expected and I can access the decorators.
But in the testing setup I get an error that the jwt decorator is undefined. It seems that the decorators are not exposed and I just can't find any error. For the tests I use node-tap with this command: tap \"test/**/*.test.js\" --reporter=list
app.js
import { dirname, join } from 'path'
import autoload from '#fastify/autoload'
import { fileURLToPath } from 'url'
import jwt from '#fastify/jwt'
export const options = {
ignoreTrailingSlash: true,
logger: true
}
export default async (fastify, opts) => {
await fastify.register(jwt, {
secret: process.env.JWT_SECRET
})
// autoload plugins and routes
await fastify.register(autoload, {
dir: join(dirname(fileURLToPath(import.meta.url)), 'plugins'),
options: Object.assign({}, opts),
forceESM: true,
})
await fastify.register(autoload, {
dir: join(dirname(fileURLToPath(import.meta.url)), 'routes'),
options: Object.assign({}, opts),
forceESM: true
})
}
helper.js
import { fileURLToPath } from 'url'
import helper from 'fastify-cli/helper.js'
import path from 'path'
// config for testing
export const config = () => {
return {}
}
export const build = async (t) => {
const argv = [
path.join(path.dirname(fileURLToPath(import.meta.url)), '..', 'src', 'app.js')
]
const app = await helper.build(argv, config())
t.teardown(app.close.bind(app))
return app
}
root.test.js
import { auth, build } from '../helper.js'
import { test } from 'tap'
test('requests the "/" route', async t => {
t.plan(1)
const app = await build(t)
const token = app.jwt.sign({ ... }) //-> jwt is undefined
const res = await app.inject({
method: 'GET',
url: '/'
})
t.equal(res.statusCode, 200, 'returns a status code of 200')
})

Answer 1

The issue is that your application diagram looks like this:
and when you write const app = await build(t) the app variable points to Root Context, but Your app.js contains the jwt decorator.
To solve it, you need just to wrap you app.js file with the fastify-plugin because it breaks the encapsulation:
import fp from 'fastify-plugin'
export default fp(async (fastify, opts) => { ... })
Note: you can visualize this structure by using fastify-overview (and the fastify-overview-ui plugin together: