[ruby/irb] Add tests about IRB history

https://github.com/ruby/irb/commit/82efd370eb

test/irb/test_history.rb

@@ -0,0 +1,131 @@
+# frozen_string_literal: false
+require 'test/unit'
+
+module TestIRB
+  class TestHistory < Test::Unit::TestCase
+    def setup
+      IRB.conf[:RC_NAME_GENERATOR] = nil
+    end
+
+    def teardown
+      IRB.conf[:RC_NAME_GENERATOR] = nil
+    end
+
+    def test_history_save_1
+      result_output, result_history_file = launch_irb_with_irbrc_and_irb_history(<<~IRBRC, <<~IRB_HISTORY) do |stdin|
+        IRB.conf[:USE_READLINE] = true
+        IRB.conf[:SAVE_HISTORY] = 1
+      IRBRC
+        1
+        2
+        3
+        4
+      IRB_HISTORY
+        stdin.write("5\nexit\n")
+      end
+
+      assert_equal(<<~HISTORY_FILE, result_history_file)
+        exit
+      HISTORY_FILE
+    end
+
+    def test_history_save_100
+      result_output, result_history_file = launch_irb_with_irbrc_and_irb_history(<<~IRBRC, <<~IRB_HISTORY) do |stdin|
+        IRB.conf[:USE_READLINE] = true
+        IRB.conf[:SAVE_HISTORY] = 100
+      IRBRC
+        1
+        2
+        3
+        4
+      IRB_HISTORY
+        stdin.write("5\nexit\n")
+      end
+
+      assert_equal(<<~HISTORY_FILE, result_history_file)
+        1
+        2
+        3
+        4
+        5
+        exit
+      HISTORY_FILE
+    end
+
+    private
+
+    def launch_irb_with_irbrc_and_irb_history(irbrc, irb_history)
+      result = nil
+      result_history = nil
+      backup_irbrc = ENV.delete("IRBRC")
+      backup_home = ENV["HOME"]
+      Dir.mktmpdir("test_irb_history_#{$$}") do |tmpdir|
+        ENV["HOME"] = tmpdir
+        open(IRB.rc_file, "w") do |f|
+          f.write(irbrc)
+        end
+        open(IRB.rc_file("_history"), "w") do |f|
+          f.write(irb_history)
+        end
+
+        with_temp_stdio do |stdin, stdout|
+          replace_stdio(stdin.path, stdout.path) do
+            bundle_exec = ENV.key?('BUNDLE_GEMFILE') ? ['-rbundler/setup'] : []
+            cmds = %W[ruby] + bundle_exec + %W[-W0 -rirb -e 'IRB.start(__FILE__)']
+            yield(stdin, stdout)
+            stdin.close
+            system(cmds.join(' '))
+            stdout.flush
+            result = stdout.read
+            stdout.close
+          end
+        end
+        open(IRB.rc_file("_history"), "r") do |f|
+          result_history = f.read
+        end
+      end
+      [result, result_history]
+    ensure
+      ENV["HOME"] = backup_home
+      ENV["IRBRC"] = backup_irbrc
+    end
+
+    def with_temp_stdio
+      Tempfile.create("test_readline_stdin") do |stdin|
+        Tempfile.create("test_readline_stdout") do |stdout|
+          yield stdin, stdout
+          if /mswin|mingw/ =~ RUBY_PLATFORM
+            # needed since readline holds refs to tempfiles, can't delete on Windows
+            #Readline.input = STDIN
+            #Readline.output = STDOUT
+          end
+        end
+      end
+    end
+
+    def replace_stdio(stdin_path, stdout_path)
+      open(stdin_path, "r") do |stdin|
+        open(stdout_path, "w") do |stdout|
+          orig_stdin = STDIN.dup
+          orig_stdout = STDOUT.dup
+          orig_stderr = STDERR.dup
+          STDIN.reopen(stdin)
+          STDOUT.reopen(stdout)
+          STDERR.reopen(stdout)
+          begin
+            #Readline.input = STDIN
+            #Readline.output = STDOUT
+            yield
+          ensure
+            STDERR.reopen(orig_stderr)
+            STDIN.reopen(orig_stdin)
+            STDOUT.reopen(orig_stdout)
+            orig_stdin.close
+            orig_stdout.close
+            orig_stderr.close
+          end
+        end
+      end
+    end
+  end
+end