I now have the code working upto the cart on the page.
Elixir and Phoenix are still great for showing exactly where the error is.
This can be handy as Elixir is very picky on whitespace usage.
Frequent use of:
mix clean
mix phx.routes
Will show any compiler warnings. It’s best to keep on top of these as they do give you clues as to obvious typos. This is especially true of unused variables.
It’s great that a whole chapter was written test first – especially when this demonstrates the DDD concept of Contexts. This is my main bugbear on some of the other Elixir books – tests have been removed to save space.
Also when you add a Plug you need to restart the server – these are not automatically added.
Developer Rants 