Node.js: Run mocha tests in a request callback - node.js

Question

I want to run some tests whose settings need to be downloaded first via a HTTP GET.
My download is successful but my test does not run when it's inside the request callback. I know it's not the best structure but I'd also like to know why this is not working.
describe('test', () => {
request.get({
url: 'https://google.com',
}, (err, status, body) => {
// The content is downloaded successfully.
console.log(body);
// This test never runs, why?
it('should be able to run inside a request.get', () => {
});
});
});
I know this code works but I would still like to know why the previous example does not.
describe('test', () => {
it('should be able to run inside a request.get', () => {
request.get({
url: 'https://google.com',
}, (err, status, body) => {
console.log(body);
});
});
});
EDIT: The suggestion provided by Jankapunkt's comment works: Moving the 'it' and 'describe' together allows for a successful download and test run.
request.get({
url: 'https://google.com',
}, (err, status, body) => {
// The content is downloaded successfully.
console.log(body);
// The describe and it are within the same closure.
describe('test', () => {
// This test runs successfully.
it('should be able to run inside a request.get', () => {
});
});
});

Answer 1

Old subject but I did like this for a Mock mongo connection:
const manager = require('./manager')
const assert = require('assert')
const MongoClient = require('./MockMongo')
let conn
describe('test execution', function() {
it('db connection', function (done) {
MongoClient.connect('test url')
.then((db) => {
conn = db
done()
})
})
it('test 1', function (done) {
manager.methodOfManager(conn, 'param1', 'param2')
.then(r => {
assert.equal(r.result, 'ok')
done()
})
.catch(err => {
console.log(err.message)
done(err)
})
})
})
It will print:
test execution
✓ db connection (5ms)
✓ Test 1 (sepa) (125ms)
2 passing (0s)

Answer 2

Approach 1: Tests inside your GET result
Use describe() around the it() within the callback function and avoid arrow functions like the following:
it("...", () => {});
It is discouraged in mocha when you have changing contexts.
Instead use
it("...", function(){});
and use .bind , done() or promises when required in async tests.
Putting this together into your code example, you may find your code to be similar to the following:
request.get({
url: 'https://google.com',
}, (err, status, body) => {
// The content is downloaded successfully.
describe('test', function() {
it('should be able to run inside a request.get', function() {
assert.isDefined(status);
assert.isDefined(body);
//...and so on
});
});
});
By the way - it is only a bad structure if for your approach is a better structure available.
Approach 2 - Wrap request.get in your unit
This is (in my opinion) the better and more mocha-like approach, where you execute the request inside the test and use the done() callback to notify mocha, that you are done:
describe('test', function() {
let request;
beforeEach(function(){
// request = ...
});
it('should be able to get a request result', function(done) {
request.get({
url: 'https://google.com',
}, (err, status, body) => {
assert.isDefined(status);
assert.isDefined(body);
//...and so on
// at the end call done
done();
});
});
You can ensure that request is initialized each test as a new fresh instance by using the beforeEach hook.