[Bug #20869] Discard read buffer and encoding converters at seeking

1 files changed, 26 insertions, 0 deletions

diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 5d4ede1e4f..0abc71a5b0 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -350,6 +350,19 @@ class TestIO < Test::Unit::TestCase
     end)
   end
 
+  def test_ungetc_with_seek
+    make_tempfile {|t|
+      t.open
+      t.write('0123456789')
+      t.rewind
+
+      t.ungetc('a')
+      t.seek(2, :SET)
+
+      assert_equal('2', t.getc)
+    }
+  end
+
   def test_ungetbyte
     make_tempfile {|t|
       t.open
@@ -373,6 +386,19 @@ class TestIO < Test::Unit::TestCase
     }
   end
 
+  def test_ungetbyte_with_seek
+    make_tempfile {|t|
+      t.open
+      t.write('0123456789')
+      t.rewind
+
+      t.ungetbyte('a'.ord)
+      t.seek(2, :SET)
+
+      assert_equal('2'.ord, t.getbyte)
+    }
+  end
+
   def test_each_byte
     pipe(proc do |w|
       w << "abc def"