Run rake assets:precompile before tests that include :js tag and skip otherwise

Question

tl;dr --

Is it possible to run a single command (e.g. rake assets:precompile ) only when there is a :js test included in the body of tests being run?

--

I'm developing a rails 5, ruby 2.3.1 app that has a large rspec test suite.

We recently installed the webpacker gem in the application which has caused us to have to run:

$ bundle exec rake assets:precompile

before running the tests. If the above command is not run the tests will be run against the most recently precompiled assets.

This has caused some headaches as developers have forgotten this step and then banged their heads against a wall until someone remembers to run that before running the test suite.

Ideally I'd like to simply add to the spec/spec_helper.rb:

config.before(:suite) do
  system('bundle exec rake assets:precompile')
end

However, this will run the precompile before every single run of the test suite or any subset therein. This will drastically slow down development time for a backend dev that is simply trying to run a single request spec that normally takes 0.15 seconds.

Additionally, we normally skip running the :js tests when developing with guard as they take too long. We just run the :js specs as a sanity check before deploying or pushing to a remote branch.

Unfortunately, adding the {:js => true} option to:

config.before(:suite, js:true)

doesn't work either, as options are ignored for the before(:suite).

Answer 1

Filter using :js tag and run once for all specs.

  ENV[ 'ASSET_PRECOMPILE_DONE' ] = nil

  config.before(:each, :js) do
    if ! ENV[ 'ASSET_PRECOMPILE_DONE' ]
      system 'bundle exec rake assets:precompile'
      ENV[ 'ASSET_PRECOMPILE_DONE' ] = 'true'
    end
  end