This is going to be a small post about an excellent tool I discovered recently. I was refactoring a large RSpect suite and trying to speed up the execution time. I wanted a reliable benchmark tool to determine where the time is spent the most and which tests are taking most of the time. That’s when I came across test-prof.

Rather than me, the official documentation of test-prof is excellent in explaining all the APIs it supports. Here it is.

Out of all the goodies the tool has, one that has found its way to most of the spec suite was the let_it_be helper it provides. Its a simple helper that avoids the usecases where you used to use instance variables in a before call to setup non-changing test data.

before do
  @draft = create(:post)
  @published = create(:post, draft: false)
 end

becomes

 let_it_be(:draft) { create(:post) }
 let_it_be(:published) { create(:post, draft: false) }

By this you can still with the goodies of proper let usage but at the same stop abusing instance variables. This and much more are documented here.