[Question] Unit test an Express middleware using cls-hooked
xballoy opened this issue · comments
Hello,
I'm trying to write a unit test to check if the value I set is well setted in my middleware.
A simplified version (the namespace 'mynamespace' is already created) of my middleware is:
module.exports = (req, res, next) => {
ns.bindEmitter(req);
ns.bindEmitter(res);
ns.run(() => {
const correlationId = uuidV4();
getNamespace('mynamespace').set('correlationId', correlationId);
next();
});
};
My failing test is:
it.only('should set a correlationId in the uuid format in the request and the response', done => {
const req = new Emitter();
const res = new Emitter();
const next = sinon.stub();
correlationIdMiddleware(ns)(req, res, next);
ns.run(() => {
const correlationId = ns.get('correlationId');
correlationId.should.satisfy(isUUID.v4);
done();
});
});
It says that correlationId is undefined. My guess is that correlationId doesn't exist anymore when I check it in my unit test.
When I run my application I can see my middleware working.
Any idea? Thanks!
It's hard to say without knowing what correlationIdMiddleware does but it looks like the context only lives during the execution of correlationIdMiddleware.
Take a look at cls-middleware and cls-hooked-sample to get an idea of the context's lifecycle in middleware and ways to test it.
Thanks. I'll have a look!
@xballoy did you resolve the issue? What is the solution?
In case anyone runs into this, this works for me:
import { ns } from '../auth/request-context';
describe('a test', () => {
let context;
beforeEach(() => {
context = ns.createContext();
ns.enter(context);
});
it('should store and retrieve a value', () => {
ns.set('key', 'value');
const response = ns.get('key');
response.should.equal('value');
});
afterEach(() => {
ns.exit(context);
});
});