1 files changed, 52 insertions, 0 deletions
diff --git a/test/ruby/test_class.rb b/test/ruby/test_class.rb
index 07c34ce9d5..710b8a6f7b 100644
--- a/test/ruby/test_class.rb
+++ b/test/ruby/test_class.rb
@@ -96,6 +96,13 @@ class TestClass < Test::Unit::TestCase
 
   def test_superclass_of_basicobject
     assert_equal(nil, BasicObject.superclass)
+
+    assert_separately([], "#{<<~"begin;"}\n#{<<~'end;'}")
+    begin;
+      module Mod end
+      BasicObject.include(Mod)
+      assert_equal(nil, BasicObject.superclass)
+    end;
   end
 
   def test_module_function
@@ -355,6 +362,17 @@ class TestClass < Test::Unit::TestCase
     assert_equal(42, PrivateClass.new.foo)
   end
 
+  def test_private_const_access
+    assert_raise_with_message NameError, /uninitialized/ do
+      begin
+        eval('class ::TestClass::PrivateClass; end')
+      rescue NameError
+      end
+
+      Object.const_get "NOT_AVAILABLE_CONST_NAME_#{__LINE__}"
+    end
+  end
+
   StrClone = String.clone
   Class.new(StrClone)
 
@@ -759,6 +777,31 @@ class TestClass < Test::Unit::TestCase
     end
   end
 
+  def test_attached_object
+    c = Class.new
+    sc = c.singleton_class
+    obj = c.new
+
+    assert_equal(obj, obj.singleton_class.attached_object)
+    assert_equal(c, sc.attached_object)
+
+    assert_raise_with_message(TypeError, /is not a singleton class/) do
+      c.attached_object
+    end
+
+    assert_raise_with_message(TypeError, /'NilClass' is not a singleton class/) do
+      nil.singleton_class.attached_object
+    end
+
+    assert_raise_with_message(TypeError, /'FalseClass' is not a singleton class/) do
+      false.singleton_class.attached_object
+    end
+
+    assert_raise_with_message(TypeError, /'TrueClass' is not a singleton class/) do
+      true.singleton_class.attached_object
+    end
+  end
+
   def test_subclass_gc
     c = Class.new
     10_000.times do
@@ -784,4 +827,13 @@ PREP
 3_000_000.times(&code)
 CODE
   end
+
+  def test_instance_freeze_dont_freeze_the_class_bug_19164
+    klass = Class.new
+    klass.prepend(Module.new)
+
+    klass.new.freeze
+    klass.define_method(:bar) {}
+    assert_equal klass, klass.remove_method(:bar), '[Bug #19164]'
+  end
 end