Add tests for mruby and move CRuby tests location.

Author: gemmaro

.gitignore

@@ -15,3 +15,4 @@ mkmf.log
 !/test/tmp/.keep
 /build_config.rb.lock
 /sample.rb
+/test.cruby/tmp/*.po

Rakefile

@@ -19,9 +19,9 @@ require "bundler/gem_tasks"
 require "rake/testtask"
 
 Rake::TestTask.new(:test) do |t|
-  t.libs << "test"
+  t.libs << "test.cruby"
   t.libs << "lib"
-  t.test_files = FileList["test/**/*_test.rb"]
+  t.test_files = FileList["test.cruby/**/*_test.rb"]
 end
 
 require "rake/extensiontask"

test.cruby/gettextpo_test.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+# Copyright (C) 2026  gemmaro
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+require_relative "test_helper"
+
+class GettextPOTest < Test::Unit::TestCase
+  def load_tests(name)
+    path = File.join(__dir__, "../test/#{name}.rb")
+    instance_eval(File.read(path), path)
+  end
+
+  test 'common with mruby' do
+    %w[
+      check
+      file
+      filepos
+      format
+      header
+      message
+      message_iterator
+      version
+    ].each do |target|
+      load_tests(target)
+    end
+  end
+
+  def _create_message_and_drop_file
+    file = GettextPO::File.new
+    iterator = file.message_iterator
+    iterator.insert("msgid1", "msgstr1")
+  end
+
+  test "dangling pointer" do
+    message = _create_message_and_drop_file
+    GC.start(full_mark: true, immediate_sweep: true)
+    assert_equal "msgid1", message.msgid
+  end
+end