Issue #9660 has been updated by _ wanabe.

Related to Feature #9711: Remove test-unit and minitest from stdlib. added

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Bug #9660: test/unit, minitest & bundler
https://bugs.ruby-lang.org/issues/9660#change-46195

* Author: Marc-Andre Lafortune
* Status: Open
* Priority: High
* Assignee: Shota Fukumori
* Category: lib
* Target version: current: 2.2.0
* ruby -v: r45033
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
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test/unit now calls `gem 'minitest'`, but this will create regressions for anyone using `bundler`.

For example, create an empty `Gemfile` and try `bundle exec ruby -e "require 'test/unit'"`

You get an error:

    .rvm/gems/ruby-head@global/gems/bundler-1.5.3/lib/bundler/rubygems_integration.rb:240:in `block in replace_gem': minitest is not part of the bundle. Add it to Gemfile. (Gem::LoadError)


See: https://github.com/ruby/ruby/commit/da61291a25faae95f33de6756b2eaa4804d5ef2b#commitcomment-5761129



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