Spring preloading and cucumber queue mode

[andrcuns]

Hi,

I have been updating our cucumber tests to the new queue mode and encountered one issue.
Because it is executing tests in chunks, we are loosing quite a bit of time on initial rails initialisation each time new chunk is started. Having ability to use spring would help with this issue, but doesn't seem it is possible at the moment with the queue runner.

I found there are 2 ways to implement this:

1. Having some sort of env var like KNAPSACK_PRO_CUCUMBER_QUEUE_SPRING_ENABLED which would transform command to a bundle exec spring cucumber.
2. Having env var similar to cucumber rake task option binary, which would allow to replace executed cucumber binary with a springified binstub.

WDYT? Maybe there are some other ways?

[ArturT]

I'm wondering if we need to consider support for something else than just spring.
I recall there is some new modern gem that's alternative to spring but I forgot the name of it and can't google it.

Regarding how this could be done. Maybe we could have a prefix and you could define it in env KNAPSACK_PRO_CUCUMBER_QUEUE_MODE_PREFIX then it could be bundle exec spring or bin/spring, or if you use something else then you could change the prefix.

prefix = ENV['KNAPSACK_PRO_CUCUMBER_QUEUE_MODE_PREFIX'] || 'bundle exec'
cmd = %Q[#{prefix} cucumber #{args} --require #{runner.test_dir} -- #{stringify_test_file_paths}]

[andrcuns]

Yeah, that works too if You want to support some other alternatives.
Quick googling showed me one other alternative written by shopify - bootsnap, looks like that one would work without any changes to exec command.
PREFIX could be also helpful if by some chance someone doesn't have bundler in path or something similar. It's up to You how to implement it, either way would work for our use case.

[ArturT]

@andrcuns I've created PR for that #98

I'm going to prepare documentation and update FAQ and release a new gem version hopefully tomorrow. In the meantime, you can test it out from the branch.

[andrcuns]

Tried running from the branch, worked as expected 👍

[ArturT]

@andrcuns I've released a new version of knapsack_pro gem 1.17.0. Please update it.

I also updated README, installation guide and added info to FAQ https://knapsackpro.com/faq/question/how-to-use-spring-gem-to-run-cucumber-tests-faster-in-queue-mode