diff --git a/ChangeLog b/ChangeLog
index cbf7794614..4ab6a66bd7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Mar 16 15:44:05 2016  Martin Duerst  <duerst@it.aoyama.ac.jp>
+
+	* test/ruby/enc/test_case_mapping.rb: Adding tests for actual Unicode
+	  case mapping. Fixing some aliasing issues.
+	  (with Kimihito Matsui)
+
 Tue Mar 15 21:38:28 2016  Tanaka Akira  <akr@fsij.org>
 
 	* enum.c (enum_inject): Consider redefinition of Fixnum#+.
diff --git a/test/ruby/enc/test_case_mapping.rb b/test/ruby/enc/test_case_mapping.rb
index 0336e3f32f..d0bcd7620c 100644
--- a/test/ruby/enc/test_case_mapping.rb
+++ b/test/ruby/enc/test_case_mapping.rb
@@ -8,31 +8,39 @@ class TestCaseMappingPreliminary < Test::Unit::TestCase
   # checks, including idempotence and non-modification; not always guaranteed
   def check_upcase_properties(expected, start, *flags)
     assert_equal expected, start.upcase(*flags)
-    temp = start
+    temp = start.dup
     assert_equal expected, temp.upcase!(*flags)
     assert_equal expected, expected.upcase(*flags)
-    temp = expected
+    temp = expected.dup
     assert_nil   temp.upcase!(*flags)
   end
 
   def check_downcase_properties(expected, start, *flags)
     assert_equal expected, start.downcase(*flags)
-    temp = start
+    temp = start.dup
     assert_equal expected, temp.downcase!(*flags)
     assert_equal expected, expected.downcase(*flags)
-    temp = expected
+    temp = expected.dup
     assert_nil   temp.downcase!(*flags)
   end
 
   def check_capitalize_properties(expected, start, *flags)
     assert_equal expected, start.capitalize(*flags)
-    temp = start
+    temp = start.dup
     assert_equal expected, temp.capitalize!(*flags)
     assert_equal expected, expected.capitalize(*flags)
-    temp = expected
+    temp = expected.dup
     assert_nil   temp.capitalize!(*flags)
   end
 
+  def check_capitalize_suffixes(lower, upper)
+    while not upper.length > 1
+      lower = lower[1..-1]
+      check_capitalize_properties upper[0]+lower, upper, :lithuanian
+      upper = upper[1..-1]
+    end
+  end
+
   # different properties; careful: roundtrip isn't always guaranteed
   def check_swapcase_properties(expected, start, *flags)
     assert_equal expected, start.swapcase(*flags)
@@ -49,6 +57,13 @@ class TestCaseMappingPreliminary < Test::Unit::TestCase
     check_swapcase_properties   'yUKIHIRO matsumoto (MAtz)', 'Yukihiro MATSUMOTO (maTZ)', :lithuanian
   end
 
+  def test_general
+    check_downcase_properties   'résumé dürst ĭñŧėřŋãţijňőńæłĩżàťïōņ', 'RÉSUMÉ DÜRST ĬÑŦĖŘŊÃŢIJŇŐŃÆŁĨŻÀŤÏŌŅ', :lithuanian
+    check_upcase_properties     'RÉSUMÉ DÜRST ĬÑŦĖŘŊÃŢIJŇŐŃÆŁĨŻÀŤÏŌŅ', 'résumé dürst ĭñŧėřŋãţijňőńæłĩżàťïōņ', :lithuanian
+    check_capitalize_suffixes   'résumé dürst ĭñŧėřŋãţijňőńæłĩżàťïōņ', 'RÉSUMÉ DÜRST ĬÑŦĖŘŊÃŢIJŇŐŃÆŁĨŻÀŤÏŌŅ'
+    check_swapcase_properties   'résumé DÜRST ĭñŧėřŊÃŢIJŇŐŃæłĩżàťïōņ', 'RÉSUMÉ dürst ĬÑŦĖŘŋãţijňőńÆŁĨŻÀŤÏŌŅ', :lithuanian
+  end
+
   def test_ascii_option
     check_downcase_properties   'yukihiro matsumoto (matz)', 'Yukihiro MATSUMOTO (MATZ)', :ascii
     check_upcase_properties     'YUKIHIRO MATSUMOTO (MATZ)', 'yukihiro matsumoto (matz)', :ascii