Author of the post here. I totally agree that comprehensive tests are still necessary. The blog post/talk don't cover this, but we actually have both kinds of tests - unit tests to test components in isolation and end-to-end tests that hit functionality from the front-end all the way to the DB.
In our experience, unit tests are useful because they run quickly (so you can run them literally every time a file changes), and let you much more quickly figure out the root cause of a failure. To us, the ability to run tests in a few seconds vs over a minute is important, because we want the dev feedback loop to be as immediate as possible. Just as we would hate waiting on slow compile times, we also hate waiting on slow tests.
That having been said, we also run comprehensive end-to-end tests before pushing changes to the site to ensure everything works properly. We think both are important to ensuring site quality and keeping the dev cycle efficient.
In our experience, unit tests are useful because they run quickly (so you can run them literally every time a file changes), and let you much more quickly figure out the root cause of a failure. To us, the ability to run tests in a few seconds vs over a minute is important, because we want the dev feedback loop to be as immediate as possible. Just as we would hate waiting on slow compile times, we also hate waiting on slow tests.
That having been said, we also run comprehensive end-to-end tests before pushing changes to the site to ensure everything works properly. We think both are important to ensuring site quality and keeping the dev cycle efficient.