I am again working through this book.
I started again with the real edition. The major change is that it is now focused on Worker Bees rather than Wildabeast’s.
So far I have made it to the testing chapter at the end of part one.
It appears that the samples have not been updated to match the latest code.
The testing techniques are really good. Given that variables are immutable then test fixtures really are reusable. The context part of ExUnit is very clear.
I understand delaying the tests to keep the book to a reasonable length, but event a single character typo can break functionality and be hard to fix later. I had misspelt the key on a lookup and though that the tests were broken.
Here is the current state https://github.com/chriseyre2000/mastery at f4d9f35
Developer Rants 