1 files changed, 102 insertions, 0 deletions
diff --git a/tool/test/test_commit_email.rb b/tool/test/test_commit_email.rb
new file mode 100644
index 0000000000..db441584fd
--- /dev/null
+++ b/tool/test/test_commit_email.rb
@@ -0,0 +1,102 @@
+require 'test/unit'
+require 'shellwords'
+require 'tmpdir'
+require 'fileutils'
+require 'open3'
+
+class TestCommitEmail < Test::Unit::TestCase
+  STDIN_DELIMITER = "---\n"
+
+  def setup
+    omit 'git command is not available' unless system('git', '--version', out: File::NULL, err: File::NULL)
+
+    @ruby = Dir.mktmpdir
+    Dir.chdir(@ruby) do
+      git('init', '--initial-branch=master')
+      git('config', 'user.name', 'Jóhän Grübél')
+      git('config', 'user.email', 'johan@example.com')
+      env = {
+        'GIT_AUTHOR_DATE' => '2025-10-08T12:00:00Z',
+        'GIT_CONFIG_GLOBAL' => @ruby + "/gitconfig",
+        'TZ' => 'UTC',
+      }
+      git('commit', '--allow-empty', '-m', 'New repository initialized by cvs2svn.', env:)
+      git('commit', '--allow-empty', '-m', 'Initial revision', env:)
+      git('commit', '--allow-empty', '-m', 'version　1.0.0', env:)
+    end
+
+    @sendmail = File.join(Dir.mktmpdir, 'sendmail')
+    File.write(@sendmail, <<~SENDMAIL, mode: "wx", perm: 0755)
+      #!/bin/sh
+      echo #{STDIN_DELIMITER.chomp.dump}
+      exec cat
+    SENDMAIL
+
+    @commit_email = File.expand_path('../../tool/commit-email.rb', __dir__)
+  end
+
+  def teardown
+    # Clean up temporary files if #setup was not omitted
+    if @sendmail
+      File.unlink(@sendmail)
+      Dir.rmdir(File.dirname(@sendmail))
+    end
+    if @ruby
+      FileUtils.rm_rf(@ruby)
+    end
+  end
+
+  def test_sendmail_encoding
+    omit 'the sendmail script does not work on windows' if windows?
+
+    Dir.chdir(@ruby) do
+      before_rev = git('rev-parse', 'HEAD^').chomp
+      after_rev = git('rev-parse', 'HEAD').chomp
+      short_rev = after_rev[0...10]
+
+      out, _, status = EnvUtil.invoke_ruby([
+        { 'SENDMAIL' => @sendmail, 'TZ' => 'UTC' }.merge!(gem_env),
+        @commit_email, './', 'cvs-admin@ruby-lang.org',
+        before_rev, after_rev, 'refs/heads/master',
+        '--viewer-uri', 'https://github.com/ruby/ruby/commit/',
+        '--error-to', 'cvs-admin@ruby-lang.org',
+      ], '', true)
+      stdin = out.b.split(STDIN_DELIMITER.b, 2).last.force_encoding('UTF-8')
+
+      assert_true(status.success?)
+      assert_equal(stdin, <<~EOS)
+        Mime-Version: 1.0
+        Content-Type: text/plain; charset=utf-8
+        Content-Transfer-Encoding: quoted-printable
+        From: =?UTF-8?B?SsOzaMOkbiBHcsO8YsOpbA==?= <noreply@ruby-lang.org>
+        To: cvs-admin@ruby-lang.org
+        Subject: #{short_rev} (master): =?UTF-8?B?dmVyc2lvbuOAgDEuMC4w?=
+        J=C3=B3h=C3=A4n Gr=C3=BCb=C3=A9l\t2025-10-08 12:00:00 +0000 (Wed, 08 Oct 2=
+        025)
+
+          New Revision: #{short_rev}
+
+          https://github.com/ruby/ruby/commit/#{short_rev}
+
+          Log:
+            version=E3=80=801.0.0=
+      EOS
+    end
+  end
+
+  private
+
+  # Resurrect the gem environment preserved by tool/test/init.rb.
+  # This should work as long as you have run `make up` or `make install`.
+  def gem_env
+    { 'GEM_PATH' => ENV['BUNDLED_GEM_PATH'], 'GEM_HOME' => ENV['BUNDLED_GEM_HOME'] }
+  end
+
+  def git(*cmd, env: {})
+    out, status = Open3.capture2(env, 'git', *cmd)
+    unless status.success?
+      raise "git #{cmd.shelljoin}\n#{out}"
+    end
+    out
+  end
+end