part4 Testing Express servers, user administration

Part4a Structure of backend application, introduction to testing

Exercises 4.1-4.2
Exercises 4.3-4.7

Part4b Testing the backend

Exercises 4.8-4.12
Exercises 4.13-4.14

Part4c User administration

part4d Token authentication

Exercises 4.15-4.23

part4e Legacy: Testing with Jest

Exercises 4.3-4.7
Exercises 4.8-4.12
Exercises 4.13-4.14