E2E tests: user login

[josecelano]

E2E tests for user login.

• Test for standard user login
• Test for admin login
• Scaffolding to arrange the database state before assertions

I've added a generic function to run SQL queries. I needed to create an account with the "admin" role. The application has only one admin, the first registered user.

There are several options to create an admin account for E2E tests.

Solution 1

We could reset the E2E test environment before running the tests, create the admin account, and finally inject the username and password as env variables into the Cypress configuration.

Pros

• There is only one admin, which is how the app works. With solution 2, we could only add one admin every time you run the test suite.

Cons

• You need to create a custom script to create the user if it does not exist. Then you get the user data (username, password) and pass the credentials to Cypress as env vars. We have to deal with a new binary. I prefer to only extend Cypress with tasks and commands.

Solution 2 (the one implemented)

• Create a Cypress custom command to register users. It's a repetitive action you want to perform on the app, like registration, login, uploading a torrent, etcetera.
• Create a Cypress custom task to grant the admin role to the newly created user. A task is a custom code you can execute in between commands.

Pros

• Simple solution, and we can use the database wrapper to arrange the state for other tests when it's slow via the UI, which is the preferred way.

Cons

• For now, we create a new admin for every test. But we can use sessions and reuse user accounts. See https://docs.cypress.io/api/commands/session#Switching-sessions-inside-tests.