Node e2e tests - async beforeEach/afterEach hooks fail on Windows - node.js

Question

On OSX and Linux, the following works great (this is as simplified a reproduction as possible, hopefully without sacrificing meaning):
import { expect } from 'chai';
import { MongoClient, Db } from 'mongodb';
import { Application, Request } from 'express';
import { Server } from 'http';
import * as config from 'config';
describe('some test', () =>
{
let Session:{ new(app:Application):Request } = require('supertest-session'),
app:Application,
server:Server,
mongoClient:MongoClient,
db:Db;
beforeEach(async () =>
{
app = express();
server = app.listen(config.Http.port);
request = new Session(app);
// On Windows tests are executed before this resolves
mongoClient = await MongoClient.connect(config.Database.connectionOptions.url);
db = mongoClient.db(config.Database.connectionOptions.database);
});
afterEach(async () =>
{
await db.dropDatabase();
request.destroy();
server.close();
});
it('works like it oughtta', () =>
{
request.post('/api/account/login')
.send({ email: 'me#example.com', password: 'password' })
.expect(200)
.then((res) =>
{
expect(res.success).to.eq(true);
})
})
});
On a Windows machine, the above fails with the following output from npm:
13 verbose stack Exit status 4
13 verbose stack at EventEmitter.<anonymous> (C:\Path\To\AppData\Roaming\nvm\v9.4.0\node_modules\npm\node_modules\npm-lifecycle\lib\index.js:285:16)
... rest of stack
13 verbose stack at Process.ChildProcess._handle.onexit (internal/child_process.js:220:5)
If I take the database connection out of the beforeEach hook and do this instead, the test will run and pass, but I still notice hard-to-track-down failures in further tests with async hooks:
before(function(done)
{
MongoClient.connect(function(err, client)
{
mongoClient = client;
done();
});
});
after(function(done)
{
mongoClient.close(function() { done(); });
});
I've seen this behavior using Mocha, Jest and FuseBox test runners. Running node#9.4 on both machines. The solution to this cannot be "just make sure I test my tests on a Windows machine before I push".