Import test assertions from ruby/ruby

4 files changed, 1154 insertions, 0 deletions

diff --git a/tests/lib/core_assertions.rb b/tests/lib/core_assertions.rb
new file mode 100644
index 0000000..abd0e45
--- /dev/null
+++ b/tests/lib/core_assertions.rb
@@ -0,0 +1,763 @@
+# frozen_string_literal: true
+
+module Test
+  module Unit
+    module Assertions
+      def _assertions= n # :nodoc:
+        @_assertions = n
+      end
+
+      def _assertions # :nodoc:
+        @_assertions ||= 0
+      end
+
+      ##
+      # Returns a proc that will output +msg+ along with the default message.
+
+      def message msg = nil, ending = nil, &default
+        proc {
+          msg = msg.call.chomp(".") if Proc === msg
+          custom_message = "#{msg}.\n" unless msg.nil? or msg.to_s.empty?
+          "#{custom_message}#{default.call}#{ending || "."}"
+        }
+      end
+    end
+
+    module CoreAssertions
+      if defined?(MiniTest)
+        require_relative '../../envutil'
+        # for ruby core testing
+        include MiniTest::Assertions
+
+        # Compatibility hack for assert_raise
+        Test::Unit::AssertionFailedError = MiniTest::Assertion
+      else
+        module MiniTest
+          class Assertion < Exception; end
+          class Skip < Assertion; end
+        end
+
+        require 'pp'
+        require_relative 'envutil'
+        include Test::Unit::Assertions
+      end
+
+      def mu_pp(obj) #:nodoc:
+        obj.pretty_inspect.chomp
+      end
+
+      def assert_file
+        AssertFile
+      end
+
+      FailDesc = proc do |status, message = "", out = ""|
+        now = Time.now
+        proc do
+          EnvUtil.failure_description(status, now, message, out)
+        end
+      end
+
+      def assert_in_out_err(args, test_stdin = "", test_stdout = [], test_stderr = [], message = nil,
+                            success: nil, **opt)
+        args = Array(args).dup
+        args.insert((Hash === args[0] ? 1 : 0), '--disable=gems')
+        stdout, stderr, status = EnvUtil.invoke_ruby(args, test_stdin, true, true, **opt)
+        desc = FailDesc[status, message, stderr]
+        if block_given?
+          raise "test_stdout ignored, use block only or without block" if test_stdout != []
+          raise "test_stderr ignored, use block only or without block" if test_stderr != []
+          yield(stdout.lines.map {|l| l.chomp }, stderr.lines.map {|l| l.chomp }, status)
+        else
+          all_assertions(desc) do |a|
+            [["stdout", test_stdout, stdout], ["stderr", test_stderr, stderr]].each do |key, exp, act|
+              a.for(key) do
+                if exp.is_a?(Regexp)
+                  assert_match(exp, act)
+                elsif exp.all? {|e| String === e}
+                  assert_equal(exp, act.lines.map {|l| l.chomp })
+                else
+                  assert_pattern_list(exp, act)
+                end
+              end
+            end
+            unless success.nil?
+              a.for("success?") do
+                if success
+                  assert_predicate(status, :success?)
+                else
+                  assert_not_predicate(status, :success?)
+                end
+              end
+            end
+          end
+          status
+        end
+      end
+
+      if defined?(RubyVM::InstructionSequence)
+        def syntax_check(code, fname, line)
+          code = code.dup.force_encoding(Encoding::UTF_8)
+          RubyVM::InstructionSequence.compile(code, fname, fname, line)
+          :ok
+        ensure
+          raise if SyntaxError === $!
+        end
+      else
+        def syntax_check(code, fname, line)
+          code = code.b
+          code.sub!(/\A(?:\xef\xbb\xbf)?(\s*\#.*$)*(\n)?/n) {
+            "#$&#{"\n" if $1 && !$2}BEGIN{throw tag, :ok}\n"
+          }
+          code = code.force_encoding(Encoding::UTF_8)
+          catch {|tag| eval(code, binding, fname, line - 1)}
+        end
+      end
+
+      def assert_no_memory_leak(args, prepare, code, message=nil, limit: 2.0, rss: false, **opt)
+        # TODO: consider choosing some appropriate limit for MJIT and stop skipping this once it does not randomly fail
+        pend 'assert_no_memory_leak may consider MJIT memory usage as leak' if defined?(RubyVM::MJIT) && RubyVM::MJIT.enabled?
+
+        require_relative '../../memory_status'
+        raise MiniTest::Skip, "unsupported platform" unless defined?(Memory::Status)
+
+        token = "\e[7;1m#{$$.to_s}:#{Time.now.strftime('%s.%L')}:#{rand(0x10000).to_s(16)}:\e[m"
+        token_dump = token.dump
+        token_re = Regexp.quote(token)
+        envs = args.shift if Array === args and Hash === args.first
+        args = [
+          "--disable=gems",
+          "-r", File.expand_path("../../../memory_status", __FILE__),
+          *args,
+          "-v", "-",
+        ]
+        if defined? Memory::NO_MEMORY_LEAK_ENVS then
+          envs ||= {}
+          newenvs = envs.merge(Memory::NO_MEMORY_LEAK_ENVS) { |_, _, _| break }
+          envs = newenvs if newenvs
+        end
+        args.unshift(envs) if envs
+        cmd = [
+          'END {STDERR.puts '"#{token_dump}"'"FINAL=#{Memory::Status.new}"}',
+          prepare,
+          'STDERR.puts('"#{token_dump}"'"START=#{$initial_status = Memory::Status.new}")',
+          '$initial_size = $initial_status.size',
+          code,
+          'GC.start',
+        ].join("\n")
+        _, err, status = EnvUtil.invoke_ruby(args, cmd, true, true, **opt)
+        before = err.sub!(/^#{token_re}START=(\{.*\})\n/, '') && Memory::Status.parse($1)
+        after = err.sub!(/^#{token_re}FINAL=(\{.*\})\n/, '') && Memory::Status.parse($1)
+        assert(status.success?, FailDesc[status, message, err])
+        ([:size, (rss && :rss)] & after.members).each do |n|
+          b = before[n]
+          a = after[n]
+          next unless a > 0 and b > 0
+          assert_operator(a.fdiv(b), :<, limit, message(message) {"#{n}: #{b} => #{a}"})
+        end
+      rescue LoadError
+        pend
+      end
+
+      # :call-seq:
+      #   assert_nothing_raised( *args, &block )
+      #
+      #If any exceptions are given as arguments, the assertion will
+      #fail if one of those exceptions are raised. Otherwise, the test fails
+      #if any exceptions are raised.
+      #
+      #The final argument may be a failure message.
+      #
+      #    assert_nothing_raised RuntimeError do
+      #      raise Exception #Assertion passes, Exception is not a RuntimeError
+      #    end
+      #
+      #    assert_nothing_raised do
+      #      raise Exception #Assertion fails
+      #    end
+      def assert_nothing_raised(*args)
+        self._assertions += 1
+        if Module === args.last
+          msg = nil
+        else
+          msg = args.pop
+        end
+        begin
+          line = __LINE__; yield
+        rescue MiniTest::Skip
+          raise
+        rescue Exception => e
+          bt = e.backtrace
+          as = e.instance_of?(MiniTest::Assertion)
+          if as
+            ans = /\A#{Regexp.quote(__FILE__)}:#{line}:in /o
+            bt.reject! {|ln| ans =~ ln}
+          end
+          if ((args.empty? && !as) ||
+              args.any? {|a| a.instance_of?(Module) ? e.is_a?(a) : e.class == a })
+            msg = message(msg) {
+              "Exception raised:\n<#{mu_pp(e)}>\n" +
+              "Backtrace:\n" +
+              e.backtrace.map{|frame| "  #{frame}"}.join("\n")
+            }
+            raise MiniTest::Assertion, msg.call, bt
+          else
+            raise
+          end
+        end
+      end
+
+      def prepare_syntax_check(code, fname = nil, mesg = nil, verbose: nil)
+        fname ||= caller_locations(2, 1)[0]
+        mesg ||= fname.to_s
+        verbose, $VERBOSE = $VERBOSE, verbose
+        case
+        when Array === fname
+          fname, line = *fname
+        when defined?(fname.path) && defined?(fname.lineno)
+          fname, line = fname.path, fname.lineno
+        else
+          line = 1
+        end
+        yield(code, fname, line, message(mesg) {
+                if code.end_with?("\n")
+                  "```\n#{code}```\n"
+                else
+                  "```\n#{code}\n```\n""no-newline"
+                end
+              })
+      ensure
+        $VERBOSE = verbose
+      end
+
+      def assert_valid_syntax(code, *args, **opt)
+        prepare_syntax_check(code, *args, **opt) do |src, fname, line, mesg|
+          yield if defined?(yield)
+          assert_nothing_raised(SyntaxError, mesg) do
+            assert_equal(:ok, syntax_check(src, fname, line), mesg)
+          end
+        end
+      end
+
+      def assert_normal_exit(testsrc, message = '', child_env: nil, **opt)
+        assert_valid_syntax(testsrc, caller_locations(1, 1)[0])
+        if child_env
+          child_env = [child_env]
+        else
+          child_env = []
+        end
+        out, _, status = EnvUtil.invoke_ruby(child_env + %W'-W0', testsrc, true, :merge_to_stdout, **opt)
+        assert !status.signaled?, FailDesc[status, message, out]
+      end
+
+      def assert_ruby_status(args, test_stdin="", message=nil, **opt)
+        out, _, status = EnvUtil.invoke_ruby(args, test_stdin, true, :merge_to_stdout, **opt)
+        desc = FailDesc[status, message, out]
+        assert(!status.signaled?, desc)
+        message ||= "ruby exit status is not success:"
+        assert(status.success?, desc)
+      end
+
+      ABORT_SIGNALS = Signal.list.values_at(*%w"ILL ABRT BUS SEGV TERM")
+
+      def separated_runner(out = nil)
+        out = out ? IO.new(out, 'w') : STDOUT
+        at_exit {
+          out.puts [Marshal.dump($!)].pack('m'), "assertions=\#{self._assertions}"
+        }
+        Test::Unit::Runner.class_variable_set(:@@stop_auto_run, true) if defined?(Test::Unit::Runner)
+      end
+
+      def assert_separately(args, file = nil, line = nil, src, ignore_stderr: nil, **opt)
+        unless file and line
+          loc, = caller_locations(1,1)
+          file ||= loc.path
+          line ||= loc.lineno
+        end
+        capture_stdout = true
+        unless /mswin|mingw/ =~ RUBY_PLATFORM
+          capture_stdout = false
+          opt[:out] = MiniTest::Unit.output if defined?(MiniTest::Unit)
+          res_p, res_c = IO.pipe
+          opt[res_c.fileno] = res_c.fileno
+        end
+        src = <<eom
+# -*- coding: #{line += __LINE__; src.encoding}; -*-
+BEGIN {
+  require "test/unit";include Test::Unit::Assertions;require #{(__dir__ + "/core_assertions").dump};include Test::Unit::CoreAssertions
+  separated_runner #{res_c&.fileno}
+}
+#{line -= __LINE__; src}
+eom
+        args = args.dup
+        args.insert((Hash === args.first ? 1 : 0), "-w", "--disable=gems", *$:.map {|l| "-I#{l}"})
+        stdout, stderr, status = EnvUtil.invoke_ruby(args, src, capture_stdout, true, **opt)
+      ensure
+        if res_c
+          res_c.close
+          res = res_p.read
+          res_p.close
+        else
+          res = stdout
+        end
+        raise if $!
+        abort = status.coredump? || (status.signaled? && ABORT_SIGNALS.include?(status.termsig))
+        assert(!abort, FailDesc[status, nil, stderr])
+        self._assertions += res[/^assertions=(\d+)/, 1].to_i
+        begin
+          res = Marshal.load(res.unpack1("m"))
+        rescue => marshal_error
+          ignore_stderr = nil
+          res = nil
+        end
+        if res and !(SystemExit === res)
+          if bt = res.backtrace
+            bt.each do |l|
+              l.sub!(/\A-:(\d+)/){"#{file}:#{line + $1.to_i}"}
+            end
+            bt.concat(caller)
+          else
+            res.set_backtrace(caller)
+          end
+          raise res
+        end
+
+        # really is it succeed?
+        unless ignore_stderr
+          # the body of assert_separately must not output anything to detect error
+          assert(stderr.empty?, FailDesc[status, "assert_separately failed with error message", stderr])
+        end
+        assert(status.success?, FailDesc[status, "assert_separately failed", stderr])
+        raise marshal_error if marshal_error
+      end
+
+      # Run Ractor-related test without influencing the main test suite
+      def assert_ractor(src, args: [], require: nil, require_relative: nil, file: nil, line: nil, ignore_stderr: nil, **opt)
+        return unless defined?(Ractor)
+
+        require = "require #{require.inspect}" if require
+        if require_relative
+          dir = File.dirname(caller_locations[0,1][0].absolute_path)
+          full_path = File.expand_path(require_relative, dir)
+          require = "#{require}; require #{full_path.inspect}"
+        end
+
+        assert_separately(args, file, line, <<~RUBY, ignore_stderr: ignore_stderr, **opt)
+          #{require}
+          previous_verbose = $VERBOSE
+          $VERBOSE = nil
+          Ractor.new {} # trigger initial warning
+          $VERBOSE = previous_verbose
+          #{src}
+        RUBY
+      end
+
+      # :call-seq:
+      #   assert_throw( tag, failure_message = nil, &block )
+      #
+      #Fails unless the given block throws +tag+, returns the caught
+      #value otherwise.
+      #
+      #An optional failure message may be provided as the final argument.
+      #
+      #    tag = Object.new
+      #    assert_throw(tag, "#{tag} was not thrown!") do
+      #      throw tag
+      #    end
+      def assert_throw(tag, msg = nil)
+        ret = catch(tag) do
+          begin
+            yield(tag)
+          rescue UncaughtThrowError => e
+            thrown = e.tag
+          end
+          msg = message(msg) {
+            "Expected #{mu_pp(tag)} to have been thrown"\
+            "#{%Q[, not #{thrown}] if thrown}"
+          }
+          assert(false, msg)
+        end
+        assert(true)
+        ret
+      end
+
+      # :call-seq:
+      #   assert_raise( *args, &block )
+      #
+      #Tests if the given block raises an exception. Acceptable exception
+      #types may be given as optional arguments. If the last argument is a
+      #String, it will be used as the error message.
+      #
+      #    assert_raise do #Fails, no Exceptions are raised
+      #    end
+      #
+      #    assert_raise NameError do
+      #      puts x  #Raises NameError, so assertion succeeds
+      #    end
+      def assert_raise(*exp, &b)
+        case exp.last
+        when String, Proc
+          msg = exp.pop
+        end
+
+        begin
+          yield
+        rescue MiniTest::Skip => e
+          return e if exp.include? MiniTest::Skip
+          raise e
+        rescue Exception => e
+          expected = exp.any? { |ex|
+            if ex.instance_of? Module then
+              e.kind_of? ex
+            else
+              e.instance_of? ex
+            end
+          }
+
+          assert expected, proc {
+            flunk(message(msg) {"#{mu_pp(exp)} exception expected, not #{mu_pp(e)}"})
+          }
+
+          return e
+        ensure
+          unless e
+            exp = exp.first if exp.size == 1
+
+            flunk(message(msg) {"#{mu_pp(exp)} expected but nothing was raised"})
+          end
+        end
+      end
+
+      # :call-seq:
+      #   assert_raise_with_message(exception, expected, msg = nil, &block)
+      #
+      #Tests if the given block raises an exception with the expected
+      #message.
+      #
+      #    assert_raise_with_message(RuntimeError, "foo") do
+      #      nil #Fails, no Exceptions are raised
+      #    end
+      #
+      #    assert_raise_with_message(RuntimeError, "foo") do
+      #      raise ArgumentError, "foo" #Fails, different Exception is raised
+      #    end
+      #
+      #    assert_raise_with_message(RuntimeError, "foo") do
+      #      raise "bar" #Fails, RuntimeError is raised but the message differs
+      #    end
+      #
+      #    assert_raise_with_message(RuntimeError, "foo") do
+      #      raise "foo" #Raises RuntimeError with the message, so assertion succeeds
+      #    end
+      def assert_raise_with_message(exception, expected, msg = nil, &block)
+        case expected
+        when String
+          assert = :assert_equal
+        when Regexp
+          assert = :assert_match
+        else
+          raise TypeError, "Expected #{expected.inspect} to be a kind of String or Regexp, not #{expected.class}"
+        end
+
+        ex = m = nil
+        EnvUtil.with_default_internal(expected.encoding) do
+          ex = assert_raise(exception, msg || proc {"Exception(#{exception}) with message matches to #{expected.inspect}"}) do
+            yield
+          end
+          m = ex.message
+        end
+        msg = message(msg, "") {"Expected Exception(#{exception}) was raised, but the message doesn't match"}
+
+        if assert == :assert_equal
+          assert_equal(expected, m, msg)
+        else
+          msg = message(msg) { "Expected #{mu_pp expected} to match #{mu_pp m}" }
+          assert expected =~ m, msg
+          block.binding.eval("proc{|_|$~=_}").call($~)
+        end
+        ex
+      end
+
+      MINI_DIR = File.join(File.dirname(File.dirname(File.expand_path(__FILE__))), "minitest") #:nodoc:
+
+      # :call-seq:
+      #   assert(test, [failure_message])
+      #
+      #Tests if +test+ is true.
+      #
+      #+msg+ may be a String or a Proc. If +msg+ is a String, it will be used
+      #as the failure message. Otherwise, the result of calling +msg+ will be
+      #used as the message if the assertion fails.
+      #
+      #If no +msg+ is given, a default message will be used.
+      #
+      #    assert(false, "This was expected to be true")
+      def assert(test, *msgs)
+        case msg = msgs.first
+        when String, Proc
+        when nil
+          msgs.shift
+        else
+          bt = caller.reject { |s| s.start_with?(MINI_DIR) }
+          raise ArgumentError, "assertion message must be String or Proc, but #{msg.class} was given.", bt
+        end unless msgs.empty?
+        super
+      end
+
+      # :call-seq:
+      #   assert_respond_to( object, method, failure_message = nil )
+      #
+      #Tests if the given Object responds to +method+.
+      #
+      #An optional failure message may be provided as the final argument.
+      #
+      #    assert_respond_to("hello", :reverse)  #Succeeds
+      #    assert_respond_to("hello", :does_not_exist)  #Fails
+      def assert_respond_to(obj, (meth, *priv), msg = nil)
+        unless priv.empty?
+          msg = message(msg) {
+            "Expected #{mu_pp(obj)} (#{obj.class}) to respond to ##{meth}#{" privately" if priv[0]}"
+          }
+          return assert obj.respond_to?(meth, *priv), msg
+        end
+        #get rid of overcounting
+        if caller_locations(1, 1)[0].path.start_with?(MINI_DIR)
+          return if obj.respond_to?(meth)
+        end
+        super(obj, meth, msg)
+      end
+
+      # :call-seq:
+      #   assert_not_respond_to( object, method, failure_message = nil )
+      #
+      #Tests if the given Object does not respond to +method+.
+      #
+      #An optional failure message may be provided as the final argument.
+      #
+      #    assert_not_respond_to("hello", :reverse)  #Fails
+      #    assert_not_respond_to("hello", :does_not_exist)  #Succeeds
+      def assert_not_respond_to(obj, (meth, *priv), msg = nil)
+        unless priv.empty?
+          msg = message(msg) {
+            "Expected #{mu_pp(obj)} (#{obj.class}) to not respond to ##{meth}#{" privately" if priv[0]}"
+          }
+          return assert !obj.respond_to?(meth, *priv), msg
+        end
+        #get rid of overcounting
+        if caller_locations(1, 1)[0].path.start_with?(MINI_DIR)
+          return unless obj.respond_to?(meth)
+        end
+        refute_respond_to(obj, meth, msg)
+      end
+
+      # pattern_list is an array which contains regexp and :*.
+      # :* means any sequence.
+      #
+      # pattern_list is anchored.
+      # Use [:*, regexp, :*] for non-anchored match.
+      def assert_pattern_list(pattern_list, actual, message=nil)
+        rest = actual
+        anchored = true
+        pattern_list.each_with_index {|pattern, i|
+          if pattern == :*
+            anchored = false
+          else
+            if anchored
+              match = /\A#{pattern}/.match(rest)
+            else
+              match = pattern.match(rest)
+            end
+            unless match
+              msg = message(msg) {
+                expect_msg = "Expected #{mu_pp pattern}\n"
+                if /\n[^\n]/ =~ rest
+                  actual_mesg = +"to match\n"
+                  rest.scan(/.*\n+/) {
+                    actual_mesg << '  ' << $&.inspect << "+\n"
+                  }
+                  actual_mesg.sub!(/\+\n\z/, '')
+                else
+                  actual_mesg = "to match " + mu_pp(rest)
+                end
+                actual_mesg << "\nafter #{i} patterns with #{actual.length - rest.length} characters"
+                expect_msg + actual_mesg
+              }
+              assert false, msg
+            end
+            rest = match.post_match
+            anchored = true
+          end
+        }
+        if anchored
+          assert_equal("", rest)
+        end
+      end
+
+      def assert_warning(pat, msg = nil)
+        result = nil
+        stderr = EnvUtil.with_default_internal(pat.encoding) {
+          EnvUtil.verbose_warning {
+            result = yield
+          }
+        }
+        msg = message(msg) {diff pat, stderr}
+        assert(pat === stderr, msg)
+        result
+      end
+
+      def assert_warn(*args)
+        assert_warning(*args) {$VERBOSE = false; yield}
+      end
+
+      def assert_deprecated_warning(mesg = /deprecated/)
+        assert_warning(mesg) do
+          Warning[:deprecated] = true
+          yield
+        end
+      end
+
+      def assert_deprecated_warn(mesg = /deprecated/)
+        assert_warn(mesg) do
+          Warning[:deprecated] = true
+          yield
+        end
+      end
+
+      class << (AssertFile = Struct.new(:failure_message).new)
+        include CoreAssertions
+        def assert_file_predicate(predicate, *args)
+          if /\Anot_/ =~ predicate
+            predicate = $'
+            neg = " not"
+          end
+          result = File.__send__(predicate, *args)
+          result = !result if neg
+          mesg = "Expected file ".dup << args.shift.inspect
+          mesg << "#{neg} to be #{predicate}"
+          mesg << mu_pp(args).sub(/\A\[(.*)\]\z/m, '(\1)') unless args.empty?
+          mesg << " #{failure_message}" if failure_message
+          assert(result, mesg)
+        end
+        alias method_missing assert_file_predicate
+
+        def for(message)
+          clone.tap {|a| a.failure_message = message}
+        end
+      end
+
+      class AllFailures
+        attr_reader :failures
+
+        def initialize
+          @count = 0
+          @failures = {}
+        end
+
+        def for(key)
+          @count += 1
+          yield
+        rescue Exception => e
+          @failures[key] = [@count, e]
+        end
+
+        def foreach(*keys)
+          keys.each do |key|
+            @count += 1
+            begin
+              yield key
+            rescue Exception => e
+              @failures[key] = [@count, e]
+            end
+          end
+        end
+
+        def message
+          i = 0
+          total = @count.to_s
+          fmt = "%#{total.size}d"
+          @failures.map {|k, (n, v)|
+            v = v.message
+            "\n#{i+=1}. [#{fmt%n}/#{total}] Assertion for #{k.inspect}\n#{v.b.gsub(/^/, '   | ').force_encoding(v.encoding)}"
+          }.join("\n")
+        end
+
+        def pass?
+          @failures.empty?
+        end
+      end
+
+      # threads should respond to shift method.
+      # Array can be used.
+      def assert_join_threads(threads, message = nil)
+        errs = []
+        values = []
+        while th = threads.shift
+          begin
+            values << th.value
+          rescue Exception
+            errs << [th, $!]
+            th = nil
+          end
+        end
+        values
+      ensure
+        if th&.alive?
+          th.raise(Timeout::Error.new)
+          th.join rescue errs << [th, $!]
+        end
+        if !errs.empty?
+          msg = "exceptions on #{errs.length} threads:\n" +
+            errs.map {|t, err|
+            "#{t.inspect}:\n" +
+              RUBY_VERSION >= "2.5.0" ? err.full_message(highlight: false, order: :top) : err.message
+          }.join("\n---\n")
+          if message
+            msg = "#{message}\n#{msg}"
+          end
+          raise MiniTest::Assertion, msg
+        end
+      end
+
+      def assert_all_assertions(msg = nil)
+        all = AllFailures.new
+        yield all
+      ensure
+        assert(all.pass?, message(msg) {all.message.chomp(".")})
+      end
+      alias all_assertions assert_all_assertions
+
+      def message(msg = nil, *args, &default) # :nodoc:
+        if Proc === msg
+          super(nil, *args) do
+            ary = [msg.call, (default.call if default)].compact.reject(&:empty?)
+            if 1 < ary.length
+              ary[0...-1] = ary[0...-1].map {|str| str.sub(/(?<!\.)\z/, '.') }
+            end
+            begin
+              ary.join("\n")
+            rescue Encoding::CompatibilityError
+              ary.map(&:b).join("\n")
+            end
+          end
+        else
+          super
+        end
+      end
+
+      def diff(exp, act)
+        require 'pp'
+        q = PP.new(+"")
+        q.guard_inspect_key do
+          q.group(2, "expected: ") do
+            q.pp exp
+          end
+          q.text q.newline
+          q.group(2, "actual: ") do
+            q.pp act
+          end
+          q.flush
+        end
+        q.output
+      end
+    end
+  end
+end
diff --git a/tests/lib/envutil.rb b/tests/lib/envutil.rb
new file mode 100644
index 0000000..323d710
--- /dev/null
+++ b/tests/lib/envutil.rb
@@ -0,0 +1,365 @@
+# -*- coding: us-ascii -*-
+# frozen_string_literal: true
+require "open3"
+require "timeout"
+require_relative "find_executable"
+begin
+  require 'rbconfig'
+rescue LoadError
+end
+begin
+  require "rbconfig/sizeof"
+rescue LoadError
+end
+
+module EnvUtil
+  def rubybin
+    if ruby = ENV["RUBY"]
+      return ruby
+    end
+    ruby = "ruby"
+    exeext = RbConfig::CONFIG["EXEEXT"]
+    rubyexe = (ruby + exeext if exeext and !exeext.empty?)
+    3.times do
+      if File.exist? ruby and File.executable? ruby and !File.directory? ruby
+        return File.expand_path(ruby)
+      end
+      if rubyexe and File.exist? rubyexe and File.executable? rubyexe
+        return File.expand_path(rubyexe)
+      end
+      ruby = File.join("..", ruby)
+    end
+    if defined?(RbConfig.ruby)
+      RbConfig.ruby
+    else
+      "ruby"
+    end
+  end
+  module_function :rubybin
+
+  LANG_ENVS = %w"LANG LC_ALL LC_CTYPE"
+
+  DEFAULT_SIGNALS = Signal.list
+  DEFAULT_SIGNALS.delete("TERM") if /mswin|mingw/ =~ RUBY_PLATFORM
+
+  RUBYLIB = ENV["RUBYLIB"]
+
+  class << self
+    attr_accessor :timeout_scale
+    attr_reader :original_internal_encoding, :original_external_encoding,
+                :original_verbose, :original_warning
+
+    def capture_global_values
+      @original_internal_encoding = Encoding.default_internal
+      @original_external_encoding = Encoding.default_external
+      @original_verbose = $VERBOSE
+      @original_warning = %i[deprecated experimental].to_h {|i| [i, Warning[i]]}
+    end
+  end
+
+  def apply_timeout_scale(t)
+    if scale = EnvUtil.timeout_scale
+      t * scale
+    else
+      t
+    end
+  end
+  module_function :apply_timeout_scale
+
+  def timeout(sec, klass = nil, message = nil, &blk)
+    return yield(sec) if sec == nil or sec.zero?
+    sec = apply_timeout_scale(sec)
+    Timeout.timeout(sec, klass, message, &blk)
+  end
+  module_function :timeout
+
+  def terminate(pid, signal = :TERM, pgroup = nil, reprieve = 1)
+    reprieve = apply_timeout_scale(reprieve) if reprieve
+
+    signals = Array(signal).select do |sig|
+      DEFAULT_SIGNALS[sig.to_s] or
+        DEFAULT_SIGNALS[Signal.signame(sig)] rescue false
+    end
+    signals |= [:ABRT, :KILL]
+    case pgroup
+    when 0, true
+      pgroup = -pid
+    when nil, false
+      pgroup = pid
+    end
+
+    lldb = true if /darwin/ =~ RUBY_PLATFORM
+
+    while signal = signals.shift
+
+      if lldb and [:ABRT, :KILL].include?(signal)
+        lldb = false
+        # sudo -n: --non-interactive
+        # lldb -p: attach
+        #      -o: run command
+        system(*%W[sudo -n lldb -p #{pid} --batch -o bt\ all -o call\ rb_vmdebug_stack_dump_all_threads() -o quit])
+        true
+      end
+
+      begin
+        Process.kill signal, pgroup
+      rescue Errno::EINVAL
+        next
+      rescue Errno::ESRCH
+        break
+      end
+      if signals.empty? or !reprieve
+        Process.wait(pid)
+      else
+        begin
+          Timeout.timeout(reprieve) {Process.wait(pid)}
+        rescue Timeout::Error
+        else
+          break
+        end
+      end
+    end
+    $?
+  end
+  module_function :terminate
+
+  def invoke_ruby(args, stdin_data = "", capture_stdout = false, capture_stderr = false,
+                  encoding: nil, timeout: 10, reprieve: 1, timeout_error: Timeout::Error,
+                  stdout_filter: nil, stderr_filter: nil,
+                  signal: :TERM,
+                  rubybin: EnvUtil.rubybin, precommand: nil,
+                  **opt)
+    timeout = apply_timeout_scale(timeout)
+
+    in_c, in_p = IO.pipe
+    out_p, out_c = IO.pipe if capture_stdout
+    err_p, err_c = IO.pipe if capture_stderr && capture_stderr != :merge_to_stdout
+    opt[:in] = in_c
+    opt[:out] = out_c if capture_stdout
+    opt[:err] = capture_stderr == :merge_to_stdout ? out_c : err_c if capture_stderr
+    if encoding
+      out_p.set_encoding(encoding) if out_p
+      err_p.set_encoding(encoding) if err_p
+    end
+    c = "C"
+    child_env = {}
+    LANG_ENVS.each {|lc| child_env[lc] = c}
+    if Array === args and Hash === args.first
+      child_env.update(args.shift)
+    end
+    if RUBYLIB and lib = child_env["RUBYLIB"]
+      child_env["RUBYLIB"] = [lib, RUBYLIB].join(File::PATH_SEPARATOR)
+    end
+    child_env['ASAN_OPTIONS'] = ENV['ASAN_OPTIONS'] if ENV['ASAN_OPTIONS']
+    args = [args] if args.kind_of?(String)
+    pid = spawn(child_env, *precommand, rubybin, *args, **opt)
+    in_c.close
+    out_c&.close
+    out_c = nil
+    err_c&.close
+    err_c = nil
+    if block_given?
+      return yield in_p, out_p, err_p, pid
+    else
+      th_stdout = Thread.new { out_p.read } if capture_stdout
+      th_stderr = Thread.new { err_p.read } if capture_stderr && capture_stderr != :merge_to_stdout
+      in_p.write stdin_data.to_str unless stdin_data.empty?
+      in_p.close
+      if (!th_stdout || th_stdout.join(timeout)) && (!th_stderr || th_stderr.join(timeout))
+        timeout_error = nil
+      else
+        status = terminate(pid, signal, opt[:pgroup], reprieve)
+        terminated = Time.now
+      end
+      stdout = th_stdout.value if capture_stdout
+      stderr = th_stderr.value if capture_stderr && capture_stderr != :merge_to_stdout
+      out_p.close if capture_stdout
+      err_p.close if capture_stderr && capture_stderr != :merge_to_stdout
+      status ||= Process.wait2(pid)[1]
+      stdout = stdout_filter.call(stdout) if stdout_filter
+      stderr = stderr_filter.call(stderr) if stderr_filter
+      if timeout_error
+        bt = caller_locations
+        msg = "execution of #{bt.shift.label} expired timeout (#{timeout} sec)"
+        msg = failure_description(status, terminated, msg, [stdout, stderr].join("\n"))
+        raise timeout_error, msg, bt.map(&:to_s)
+      end
+      return stdout, stderr, status
+    end
+  ensure
+    [th_stdout, th_stderr].each do |th|
+      th.kill if th
+    end
+    [in_c, in_p, out_c, out_p, err_c, err_p].each do |io|
+      io&.close
+    end
+    [th_stdout, th_stderr].each do |th|
+      th.join if th
+    end
+  end
+  module_function :invoke_ruby
+
+  def verbose_warning
+    class << (stderr = "".dup)
+      alias write concat
+      def flush; end
+    end
+    stderr, $stderr = $stderr, stderr
+    $VERBOSE = true
+    yield stderr
+    return $stderr
+  ensure
+    stderr, $stderr = $stderr, stderr
+    $VERBOSE = EnvUtil.original_verbose
+    EnvUtil.original_warning.each {|i, v| Warning[i] = v}
+  end
+  module_function :verbose_warning
+
+  def default_warning
+    $VERBOSE = false
+    yield
+  ensure
+    $VERBOSE = EnvUtil.original_verbose
+  end
+  module_function :default_warning
+
+  def suppress_warning
+    $VERBOSE = nil
+    yield
+  ensure
+    $VERBOSE = EnvUtil.original_verbose
+  end
+  module_function :suppress_warning
+
+  def under_gc_stress(stress = true)
+    stress, GC.stress = GC.stress, stress
+    yield
+  ensure
+    GC.stress = stress
+  end
+  module_function :under_gc_stress
+
+  def with_default_external(enc)
+    suppress_warning { Encoding.default_external = enc }
+    yield
+  ensure
+    suppress_warning { Encoding.default_external = EnvUtil.original_external_encoding }
+  end
+  module_function :with_default_external
+
+  def with_default_internal(enc)
+    suppress_warning { Encoding.default_internal = enc }
+    yield
+  ensure
+    suppress_warning { Encoding.default_internal = EnvUtil.original_internal_encoding }
+  end
+  module_function :with_default_internal
+
+  def labeled_module(name, &block)
+    Module.new do
+      singleton_class.class_eval {
+        define_method(:to_s) {name}
+        alias inspect to_s
+        alias name to_s
+      }
+      class_eval(&block) if block
+    end
+  end
+  module_function :labeled_module
+
+  def labeled_class(name, superclass = Object, &block)
+    Class.new(superclass) do
+      singleton_class.class_eval {
+        define_method(:to_s) {name}
+        alias inspect to_s
+        alias name to_s
+      }
+      class_eval(&block) if block
+    end
+  end
+  module_function :labeled_class
+
+  if /darwin/ =~ RUBY_PLATFORM
+    DIAGNOSTIC_REPORTS_PATH = File.expand_path("~/Library/Logs/DiagnosticReports")
+    DIAGNOSTIC_REPORTS_TIMEFORMAT = '%Y-%m-%d-%H%M%S'
+    @ruby_install_name = RbConfig::CONFIG['RUBY_INSTALL_NAME']
+
+    def self.diagnostic_reports(signame, pid, now)
+      return unless %w[ABRT QUIT SEGV ILL TRAP].include?(signame)
+      cmd = File.basename(rubybin)
+      cmd = @ruby_install_name if "ruby-runner#{RbConfig::CONFIG["EXEEXT"]}" == cmd
+      path = DIAGNOSTIC_REPORTS_PATH
+      timeformat = DIAGNOSTIC_REPORTS_TIMEFORMAT
+      pat = "#{path}/#{cmd}_#{now.strftime(timeformat)}[-_]*.crash"
+      first = true
+      30.times do
+        first ? (first = false) : sleep(0.1)
+        Dir.glob(pat) do |name|
+          log = File.read(name) rescue next
+          if /\AProcess:\s+#{cmd} \[#{pid}\]$/ =~ log
+            File.unlink(name)
+            File.unlink("#{path}/.#{File.basename(name)}.plist") rescue nil
+            return log
+          end
+        end
+      end
+      nil
+    end
+  else
+    def self.diagnostic_reports(signame, pid, now)
+    end
+  end
+
+  def self.failure_description(status, now, message = "", out = "")
+    pid = status.pid
+    if signo = status.termsig
+      signame = Signal.signame(signo)
+      sigdesc = "signal #{signo}"
+    end
+    log = diagnostic_reports(signame, pid, now)
+    if signame
+      sigdesc = "SIG#{signame} (#{sigdesc})"
+    end
+    if status.coredump?
+      sigdesc = "#{sigdesc} (core dumped)"
+    end
+    full_message = ''.dup
+    message = message.call if Proc === message
+    if message and !message.empty?
+      full_message << message << "\n"
+    end
+    full_message << "pid #{pid}"
+    full_message << " exit #{status.exitstatus}" if status.exited?
+    full_message << " killed by #{sigdesc}" if sigdesc
+    if out and !out.empty?
+      full_message << "\n" << out.b.gsub(/^/, '| ')
+      full_message.sub!(/(?<!\n)\z/, "\n")
+    end
+    if log
+      full_message << "Diagnostic reports:\n" << log.b.gsub(/^/, '| ')
+    end
+    full_message
+  end
+
+  def self.gc_stress_to_class?
+    unless defined?(@gc_stress_to_class)
+      _, _, status = invoke_ruby(["-e""exit GC.respond_to?(:add_stress_to_class)"])
+      @gc_stress_to_class = status.success?
+    end
+    @gc_stress_to_class
+  end
+end
+
+if defined?(RbConfig)
+  module RbConfig
+    @ruby = EnvUtil.rubybin
+    class << self
+      undef ruby if method_defined?(:ruby)
+      attr_reader :ruby
+    end
+    dir = File.dirname(ruby)
+    CONFIG['bindir'] = dir
+  end
+end
+
+EnvUtil.capture_global_values
diff --git a/tests/lib/find_executable.rb b/tests/lib/find_executable.rb
new file mode 100644
index 0000000..89c6fb8
--- /dev/null
+++ b/tests/lib/find_executable.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+require "rbconfig"
+
+module EnvUtil
+  def find_executable(cmd, *args)
+    exts = RbConfig::CONFIG["EXECUTABLE_EXTS"].split | [RbConfig::CONFIG["EXEEXT"]]
+    ENV["PATH"].split(File::PATH_SEPARATOR).each do |path|
+      next if path.empty?
+      path = File.join(path, cmd)
+      exts.each do |ext|
+        cmdline = [path + ext, *args]
+        begin
+          return cmdline if yield(IO.popen(cmdline, "r", err: [:child, :out], &:read))
+        rescue
+          next
+        end
+      end
+    end
+    nil
+  end
+  module_function :find_executable
+end
diff --git a/tests/lib/helper.rb b/tests/lib/helper.rb
new file mode 100644
index 0000000..909f8f9
--- /dev/null
+++ b/tests/lib/helper.rb
@@ -0,0 +1,4 @@
+require "test/unit"
+require_relative "core_assertions"
+
+Test::Unit::TestCase.include Test::Unit::CoreAssertions