Merge #2972

2972: Remove 1.8.7 leftovers r=bronzdoc a=deivid-rodriguez

# Description:

Cleanup some leftover code from ruby 1.8.7 times.

# Tasks:

- [x] Describe the problem / feature
- [ ] Write tests
- [x] Write code to solve the problem
- [ ] Get code review from coworkers / friends

I will abide by the [code of conduct](https://github.com/rubygems/rubygems/blob/master/CODE_OF_CONDUCT.md).


Co-authored-by: David Rodríguez <deivid.rodriguez@riseup.net>

lib/rubygems.rb

@@ -160,24 +160,14 @@ module Gem
   ].freeze
 
   ##
-  # Exception classes used in a Gem.read_binary +rescue+ statement. Not all of
-  # these are defined in Ruby 1.8.7, hence the need for this convoluted setup.
+  # Exception classes used in a Gem.read_binary +rescue+ statement
 
-  READ_BINARY_ERRORS = begin
-    read_binary_errors = [Errno::EACCES, Errno::EROFS, Errno::ENOSYS]
-    read_binary_errors << Errno::ENOTSUP if Errno.const_defined?(:ENOTSUP)
-    read_binary_errors
-  end.freeze
+  READ_BINARY_ERRORS = [Errno::EACCES, Errno::EROFS, Errno::ENOSYS, Errno::ENOTSUP].freeze
 
   ##
-  # Exception classes used in Gem.write_binary +rescue+ statement. Not all of
-  # these are defined in Ruby 1.8.7.
+  # Exception classes used in Gem.write_binary +rescue+ statement
 
-  WRITE_BINARY_ERRORS = begin
-    write_binary_errors = [Errno::ENOSYS]
-    write_binary_errors << Errno::ENOTSUP if Errno.const_defined?(:ENOTSUP)
-    write_binary_errors
-  end.freeze
+  WRITE_BINARY_ERRORS = [Errno::ENOSYS, Errno::ENOTSUP].freeze
 
   @@win_platform = nil
 

lib/rubygems/commands/setup_command.rb

@@ -98,7 +98,7 @@ def initialize
   end
 
   def check_ruby_version
-    required_version = Gem::Requirement.new '>= 1.8.7'
+    required_version = Gem::Requirement.new '>= 2.3.0'
 
     unless required_version.satisfied_by? Gem.ruby_version
       alert_error "Expected Ruby version #{required_version}, is #{Gem.ruby_version}"

test/rubygems/test_gem_commands_help_command.rb

@@ -4,20 +4,15 @@
 require "rubygems/commands/help_command"
 require "rubygems/package"
 require "rubygems/command_manager"
-require File.expand_path('../rubygems_plugin', __FILE__)
 
 class TestGemCommandsHelpCommand < Gem::TestCase
 
-  # previously this was calc'd in setup, but 1.8.7 had
-  # intermittent failures, but no issues with above require
-  PLUGIN = File.expand_path('../rubygems_plugin.rb', __FILE__)
-
   def setup
     super
 
     @cmd = Gem::Commands::HelpCommand.new
 
-    load PLUGIN unless Gem::Commands.const_defined? :InterruptCommand
+    load File.expand_path('../rubygems_plugin.rb', __FILE__) unless Gem::Commands.const_defined? :InterruptCommand
   end
 
   def test_gem_help_bad