Test the CLI invocation, including logging in & preloading

[nolar]

Issue : #13

It is straightforward: no explanations needed. Just the tests and few non-critical fixes detected during the tests.

[zincr]

🤖 zincr found 0 problems , 1 warning

ℹ️ Large Commits
✅ Approvals
✅ Specification
✅ Dependency Licensing

Details on how to resolve are provided below

---

Large Commits

Checks all commits for large additions to a single file. Large commits should be reviewed more carefully for potential copyright and licensing issues

This file contains a substantial change, please review to determine if the change comes from an external source and if there are any copyright or licensing issues to be aware of

• ℹ️ tests/cli/test_login.py had +100 lines of code changed in a single commit
  Please review this file to determine the source of this change
   

[nolar]

@samurang87 And the last time please, with all the merge conflicts with the new features resolved (and just rebased on master) ;-)