Merge json-2.3.1 from flori/json

ext/json/json.gemspec

@@ -2,7 +2,7 @@
 
 Gem::Specification.new do |s|
   s.name = "json"
-  s.version = "2.3.0"
+  s.version = "2.3.1"
 
   s.required_rubygems_version = Gem::Requirement.new(">= 0") if s.respond_to? :required_rubygems_version=
   s.require_paths = ["lib"]
@@ -135,5 +135,5 @@ Gem::Specification.new do |s|
   s.test_files = ["tests/test_helper.rb"]
 
   s.add_development_dependency("rake", [">= 0"])
-  s.add_development_dependency("test-unit", ["~> 2.0"])
+  s.add_development_dependency("test-unit", [">= 2.0", "< 4.0"])
 end

ext/json/lib/json/version.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: false
 module JSON
   # JSON version
-  VERSION         = '2.3.0'
+  VERSION         = '2.3.1'
   VERSION_ARRAY   = VERSION.split(/\./).map { |x| x.to_i } # :nodoc:
   VERSION_MAJOR   = VERSION_ARRAY[0] # :nodoc:
   VERSION_MINOR   = VERSION_ARRAY[1] # :nodoc:

test/json/test_helper.rb

@@ -1,12 +1,12 @@
 case ENV['JSON']
 when 'pure'
-  $:.unshift File.join(__dir__, '../lib')
+  $:.unshift 'lib'
   require 'json/pure'
 when 'ext'
-  $:.unshift File.join(__dir__, '../ext'), File.join(__dir__, '../lib')
+  $:.unshift 'ext', 'lib'
   require 'json/ext'
 else
-  $:.unshift File.join(__dir__, '../ext'), File.join(__dir__, '../lib')
+  $:.unshift 'ext', 'lib'
   require 'json'
 end