An easier journey: top to bottom
When you are an experienced tester, approaching a test suite is a nice road. But learning how to test properly, what to test and what to avoid, which kind of tests to choose etc. is not an easy journey.
More: testing is expensive at the beginning. Everything is new, the examples you try to implement do not work, debugging a test could be hard...
We think that approaching a test suite from the bottom to the top does not help. Starting with some unit tests is easy because they're a pretty simple topic, but does not help you with deadlines, nor having a good confidence about your app.
It's harder to manage some functional/end-to-end tests but you have more fun and, above all, you have full confidence about your app. Even if you end up having a single end-to-end (E2E from now on), this single test is more useful than having hundreds of unit tests.
Starting with the E2E tests does not only give you more confidence (and satisfaction, it's important too) but it let you understand in a while the limitations of the most confident, yet expensive, kind of tests.
That's why we teach this course following the opposite flow: from the top (E2E tests) to the bottom (unit tests).
Please note: every kind of test is important, but they serve a different purpose. At the beginning, choosing between them is hard, that's why we start exploring the tests that you can not miss(due to the best return of investment): the E2E tests.
Author: Stefano Magni