ParallelTests module not available when running through parallel_rspec?

[PragTob]

👋

Hi there and thanks a lot for your work making the life of lots of ruby devs better or well... their feedback cycles faster 💚

I'm the SimpleCov maintainer and hence need to integrate with ParallelTests quite a bit :)

So far we've used code like this to deal with some of the specifics:

    def final_result_process?
      # checking for ENV["TEST_ENV_NUMBER"] to determine if the tests are being run in parallel
      !defined?(ParallelTests) || !ENV["TEST_ENV_NUMBER"] || ParallelTests.number_of_running_processes <= 1
    end

However, debugging a case right now where I run tests via parallel_rspec I realize that the ParallelTests module isn't available 😱

As a bit of illustration this is my test file:

# frozen_string_literal: true

require "spec_helper"

p defined?(ParallelTests)

describe A do
  it "foo" do
    expect(subject.foo).to eq :foo
  end

  it "cond" do
    expect(subject.cond(false)).to eq :no
  end
end

And this is what I get:

tobi@speedy:~/github/simplecov/test_projects/parallel_tests(exit-status-refactoring)$ bundle exec parallel_rspec spec/a_spec.rb 
1 processes for 1 specs, ~ 1 specs per process
No SimpleCov config file found!
nil
..

Finished in 0.00185 seconds (files took 0.05894 seconds to load)
2 examples, 0 failures


2 examples, 0 failures

Took 0 seconds

I assumed the module would always be available from the README (and so I guess did the original author of that code)

---

I guess it's more of a question:

• is this a bug? Is this intended?
• If this is intended, what's the best way for me to get these helper functions?
  • Detect parallel tests and inline them myself?
  • detect parallel tests, require it and then call them?

Help would be much appreciated, thank you for your great work!

edit: done with the most recent ParallTests version (3.1.0)

[grosser]

it's not intended to be available since it is a CLI runner and does not modify the files under test (it can in theory not even be in the Gemfile of the repo)

[PragTob]

@grosser thanks for the answer!

What's the recommended way then to solve things as described in: https://github.com/grosser/parallel_tests#running-things-once ?

I guess since it might not even be in the Gemfile all those functions would have to inlined?

[grosser]

require would work in most cases, ParallelTests.last_process? sounds like the logic you want
(it has a race-condition where both processes could return false in parallel)

[grosser]

hmmm no that's wrong ... you want "am I the last process alive" :/

[PragTob]

@grosser yeah exactly was just typing that up, that's our "do all the last processing and fail if test coverage is too low" step & check :)

[grosser]

... so maybe use last_process and then wait for everyone else to finish with wait_for_other_processes_to_finish ?

[PragTob]

@grosser might be a solution. Not sure about the tradeoffs against our current solution of "counting" alive processes. I'll have to think/meditate about this some more. Thanks!

As for the question, I'll submit a PR to mention this in the README and then I think this can be closed :)

[grosser]

sounds similar to counting live processes, the advantage would be that there is no race condition since only 1 process would wait for everyone else to stop
👍

[PragTob]

@grosser Ah right, misunderstood what you meant where the race condition was. Thanks!

[PragTob]

Thanks a lot for your great and quick help 🎉 💚

Here, have a bunny:

[joshuapinter]

FYI, I'm using ParallelTests with the latest simplecov master and it's working great. Only a single test result output on the last process:

Using recorded test runtime
12 processes for 178 specs, ~ 14 specs per process
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Coverage report generated for (1/12), (10/12), (11/12), (12/12), (2/12), (3/12), (4/12), (5/12), (6/12), (7/12), (8/12), (9/12) to /Users/user/cntral/coverage. 6893 / 11166 LOC (61.73%) covered.