E2E Test Improvements

[hexonaut]

We've been working on some improvements to the e2e testing to ensure more code is covered and things are tested beyond just execution with sanity checks on various values. We will continue to improve this, but wondering if there is any interest in including this upstream.

Here are 3 PRs we've merged and can open a PR here if desired:

https://github.com/marsfoundation/aave-helpers/pull/10/files
https://github.com/marsfoundation/aave-helpers/pull/11/files
https://github.com/marsfoundation/aave-helpers/pull/12/files