2 files changed, 41 insertions, 0 deletions
diff --git a/test/ruby/namespace/instance_variables.rb b/test/ruby/namespace/instance_variables.rb
new file mode 100644
index 0000000000..1562ad5d45
--- /dev/null
+++ b/test/ruby/namespace/instance_variables.rb
@@ -0,0 +1,21 @@
+class String
+  class << self
+    attr_reader :str_ivar1
+
+    def str_ivar2
+      @str_ivar2
+    end
+  end
+
+  @str_ivar1 = 111
+  @str_ivar2 = 222
+end
+
+class StringDelegator < BasicObject
+private
+  def method_missing(...)
+    ::String.public_send(...)
+  end
+end
+
+StringDelegatorObj = StringDelegator.new
diff --git a/test/ruby/test_namespace.rb b/test/ruby/test_namespace.rb
index 395f244c8e..f13063be48 100644
--- a/test/ruby/test_namespace.rb
+++ b/test/ruby/test_namespace.rb
@@ -222,6 +222,26 @@ class TestNamespace < Test::Unit::TestCase
     end;
   end
 
+  def test_instance_variable
+    pend unless Namespace.enabled?
+
+    @n.require_relative('namespace/instance_variables')
+
+    assert_equal [], String.instance_variables
+    assert_equal [:@str_ivar1, :@str_ivar2], @n::StringDelegatorObj.instance_variables
+    assert_equal 111, @n::StringDelegatorObj.str_ivar1
+    assert_equal 222, @n::StringDelegatorObj.str_ivar2
+    assert_equal 222, @n::StringDelegatorObj.instance_variable_get(:@str_ivar2)
+
+    @n::StringDelegatorObj.instance_variable_set(:@str_ivar3, 333)
+    assert_equal 333, @n::StringDelegatorObj.instance_variable_get(:@str_ivar3)
+    @n::StringDelegatorObj.remove_instance_variable(:@str_ivar1)
+    assert_nil @n::StringDelegatorObj.str_ivar1
+    assert_equal [:@str_ivar2, :@str_ivar3], @n::StringDelegatorObj.instance_variables
+
+    assert_equal [], String.instance_variables
+  end
+
   def test_methods_added_in_namespace_are_invisible_globally
     pend unless Namespace.enabled?