diff --git a/activesupport/test/core_ext/module/attr_accessor_with_default.rb b/activesupport/test/core_ext/module/attr_accessor_with_default.rb
deleted file mode 100644
index e69de29bb2..0000000000
diff --git a/activesupport/test/core_ext/module/attr_internal_test.rb b/activesupport/test/core_ext/module/attr_internal_test.rb
index 25b049f619..1bf831e490 100644
--- a/activesupport/test/core_ext/module/attr_internal_test.rb
+++ b/activesupport/test/core_ext/module/attr_internal_test.rb
@@ -6,46 +6,46 @@ class AttrInternalTest < Test::Unit::TestCase
     @instance = @target.new
   end
 
-  def test_attr_internal_reader
+  def test_reader
     assert_nothing_raised { @target.attr_internal_reader :foo }
 
-    assert !@instance.instance_variables.include?('@_foo')
+    assert !@instance.instance_variable_defined?('@_foo')
     assert_raise(NoMethodError) { @instance.foo = 1 }
 
     @instance.instance_variable_set('@_foo', 1)
     assert_nothing_raised { assert_equal 1, @instance.foo }
   end
 
-  def test_attr_internal_writer
+  def test_writer
     assert_nothing_raised { @target.attr_internal_writer :foo }
 
-    assert !@instance.instance_variables.include?('@_foo')
+    assert !@instance.instance_variable_defined?('@_foo')
     assert_nothing_raised { assert_equal 1, @instance.foo = 1 }
 
     assert_equal 1, @instance.instance_variable_get('@_foo')
     assert_raise(NoMethodError) { @instance.foo }
   end
 
-  def test_attr_internal_accessor
+  def test_accessor
     assert_nothing_raised { @target.attr_internal :foo }
 
-    assert !@instance.instance_variables.include?('@_foo')
+    assert !@instance.instance_variable_defined?('@_foo')
     assert_nothing_raised { assert_equal 1, @instance.foo = 1 }
 
     assert_equal 1, @instance.instance_variable_get('@_foo')
     assert_nothing_raised { assert_equal 1, @instance.foo }
   end
 
-  def test_attr_internal_naming_format
+  def test_naming_format
     assert_equal '@_%s', @target.attr_internal_naming_format
     assert_nothing_raised { @target.attr_internal_naming_format = '@abc%sdef' }
     @target.attr_internal :foo
 
-    assert !@instance.instance_variables.include?('@_foo')
-    assert !@instance.instance_variables.include?('@abcfoodef')
+    assert !@instance.instance_variable_defined?('@_foo')
+    assert !@instance.instance_variable_defined?('@abcfoodef')
     assert_nothing_raised { @instance.foo = 1 }
-    assert !@instance.instance_variables.include?('@_foo')
-    assert @instance.instance_variables.include?('@abcfoodef')
+    assert !@instance.instance_variable_defined?('@_foo')
+    assert @instance.instance_variable_defined?('@abcfoodef')
   ensure
     @target.attr_internal_naming_format = '@_%s'
   end