diff --git a/test/digest/test_digest.rb b/test/digest/test_digest.rb
index 89f0660fc8..7cdc639340 100644
--- a/test/digest/test_digest.rb
+++ b/test/digest/test_digest.rb
@@ -88,4 +88,10 @@ class TestDigest < Test::Unit::TestCase
       assert_equal(md1, md2, algo)
     end
   end
+
+  def test_instance_eval # [ruby-dev:24202]
+    assert_nothing_raised {
+      Digest::SHA1.new.instance_eval { update "a" }
+    }
+  end
 end
diff --git a/test/ruby/test_eval.rb b/test/ruby/test_eval.rb
index 28fd01c70c..6b3fea7bb4 100644
--- a/test/ruby/test_eval.rb
+++ b/test/ruby/test_eval.rb
@@ -119,4 +119,39 @@ class TestEval < Test::Unit::TestCase
     assert_equal(5, p1.call)
     assert_nil(i7)
   end
+
+  def test_nil_instance_eval_cvar # [ruby-dev:24103]
+    def nil.test_binding
+      binding
+    end
+    bb = eval("nil.instance_eval \"binding\"", nil.test_binding)
+    assert_raise(NameError) { eval("@@a", bb) }
+    class << nil
+      remove_method :test_binding
+    end
+  end
+
+  def test_fixnum_instance_eval_cvar # [ruby-dev:24213]
+    assert_raise(NameError) { 1.instance_eval "@@a" }
+  end
+
+  def test_cvar_scope_with_instance_eval # [ruby-dev:24223]
+    Fixnum.class_eval "@@test_cvar_scope_with_instance_eval = 1" # depends on [ruby-dev:24229]
+    @@test_cvar_scope_with_instance_eval = 4
+    assert_equal(4, 1.instance_eval("@@test_cvar_scope_with_instance_eval"))
+    Fixnum.__send__(:remove_class_variable, :@@test_cvar_scope_with_instance_eval)
+  end
+
+  def test_eval_and_define_method # [ruby-dev:24228]
+    assert_nothing_raised {
+      def temporally_method_for_test_eval_and_define_method(&block)
+        lambda {
+          class << Object.new; self end.__send__(:define_method, :zzz, &block)
+        }
+      end
+      v = eval("temporally_method_for_test_eval_and_define_method {}")
+      {}[0] = {}
+      v.call
+    }
+  end
 end
diff --git a/test/ruby/test_file.rb b/test/ruby/test_file.rb
index 637dced6a6..4459c3edd9 100644
--- a/test/ruby/test_file.rb
+++ b/test/ruby/test_file.rb
@@ -226,4 +226,23 @@ class TestFile < Test::Unit::TestCase
     assert(File.fnmatch('**/foo', 'c:/root/foo', File::FNM_PATHNAME))
   end
 
+  def test_truncate_wbuf # [ruby-dev:24191]
+    f = Tempfile.new("test-truncate")
+    f.puts "abc"
+    f.truncate(0)
+    f.puts "def"
+    f.close
+    assert_equal("\0\0\0\0def\n", File.read(f.path))
+  end
+
+  def test_truncate_rbuf # [ruby-dev:24197]
+    f = Tempfile.new("test-truncate")
+    f.puts "abc"
+    f.puts "def"
+    f.close
+    f.open
+    assert_equal("abc\n", f.gets)
+    f.truncate(3)
+    assert_equal(nil, f.gets)
+  end
 end
diff --git a/test/stringio/test_stringio.rb b/test/stringio/test_stringio.rb
index a62fa491b8..cdb35e6acc 100644
--- a/test/stringio/test_stringio.rb
+++ b/test/stringio/test_stringio.rb
@@ -14,4 +14,20 @@ class TestStringIO < Test::Unit::TestCase
   alias open_file_rw open_file
 
   include TestEOF::Seek
+
+  def test_truncate # [ruby-dev:24190]
+    io = StringIO.new("")
+    io.puts "abc"
+    io.truncate(0)
+    io.puts "def"
+    assert_equal("\0\0\0def\n", io.string)
+  end
+
+  def test_seek_beyond_eof # [ruby-dev:24194]
+    io = StringIO.new
+    n = 100
+    io.seek(n)
+    io.print "last"
+    assert_equal("\0" * n + "last", io.string)
+  end
 end
diff --git a/test/zlib/test_zlib.rb b/test/zlib/test_zlib.rb
index 48e074750f..5a646cf8de 100644
--- a/test/zlib/test_zlib.rb
+++ b/test/zlib/test_zlib.rb
@@ -13,16 +13,46 @@ if defined? Zlib
     def test_read0
       assert_equal("", Zlib::GzipReader.new(StringIO.new(D0)).read(0))
     end
+
+    def test_ungetc # [ruby-dev:24060]
+      s = ""
+      w = Zlib::GzipWriter.new(StringIO.new(s))
+      w << (1...1000).to_a.inspect
+      w.close
+      r = Zlib::GzipReader.new(StringIO.new(s))
+      r.read(100)
+      r.ungetc ?a
+      assert_nothing_raised {
+        r.read(100)
+        r.read
+        r.close
+      }
+    end
+
+    def test_ungetc_paragraph # [ruby-dev:24065]
+      s = ""
+      w = Zlib::GzipWriter.new(StringIO.new(s))
+      w << "abc"
+      w.close
+      r = Zlib::GzipReader.new(StringIO.new(s))
+      $/ = ""
+      r.ungetc ?\n
+      assert_equal("abc", r.gets)
+      assert_nothing_raised {
+        r.read
+        r.close
+      }
+    end
   end
 
   class TestZlibGzipWriter < Test::Unit::TestCase
     def test_invalid_new
       # [ruby-dev:23228]
-      assert_raises(NoMethodError) { Zlib::GzipWriter.new(nil).close }
+      assert_raise(NoMethodError) { Zlib::GzipWriter.new(nil).close }
       # [ruby-dev:23344]
-      assert_raises(NoMethodError) { Zlib::GzipWriter.new(true).close }
-      assert_raises(NoMethodError) { Zlib::GzipWriter.new(0).close }
-      assert_raises(NoMethodError) { Zlib::GzipWriter.new(:hoge).close }
+      assert_raise(NoMethodError) { Zlib::GzipWriter.new(true).close }
+      assert_raise(NoMethodError) { Zlib::GzipWriter.new(0).close }
+      assert_raise(NoMethodError) { Zlib::GzipWriter.new(:hoge).close }
     end
   end
 end