add a test.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@15643 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_io_m17n.rb

@@ -426,5 +426,14 @@ EOT
       assert_equal("\u{3042}".encode("euc-jp"), result)
     }
   end
+
+  def test_file_foreach
+    with_tmpdir {
+      generate_file('tst', 'a' * 8191 + "\xa1\xa1")
+      assert_nothing_raised {
+        File.foreach('tst', :encoding=>"euc-jp") {|line| line.inspect }
+      }
+    }
+  end
 end