Rails 6 parallel tests causes parallel debuggers

[gdomingu]

Problem description

Working in a Rail 6.0.2.2 project with byebug 11.1.2. my test_helper.rb has parallelize(workers: :number_of_processors) in it by default.

When I run the test suite with rails test. I get put into parallel byebug bindings.

Expected behavior

I expect it to just put me in one binding at a time.

Actual behavior

Puts me in two byebug debuggers at once. In order to type I need to hit each key twice before it shows up in terminal.

[7, 16] in /test/models/foo_test.rb
    7:    test "it does the thing again" do
    8:     Foo.do_it
    9:   end
   10: end
   11: 
   12: class Foo
   13:   def self.do_it
   14:     byebug
=> 15:   end
   16: end

[7, 16] in /test/models/foo_test.rb
    7:    test "it does the thing again" do
    8:     Foo.do_it
    9:   end
   10: end
   11: 
   12: class Foo
   13:   def self.do_it
   14:     byebug
=> 15:   end
   16: end

Steps to reproduce the problem

1. Create a new rails 6 project.
2. Uncomment byebug from gemfile.
3. Bundle
4. Make sure parallelize(workers: :number_of_processors) is in test_helper.rb
5. Create a test like the following:

require 'test_helper'

class FooTest < ActiveSupport::TestCase
  test "it does the thing" do
    Foo.do_it
  end
   test "it does the thing again" do
    Foo.do_it
  end
end

class Foo
  def self.do_it
    byebug
  end
end

6. Run bundle exec rails test

[wilg]

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