1 files changed, 10 insertions, 2 deletions
diff --git a/spec/ruby/core/io/new_spec.rb b/spec/ruby/core/io/new_spec.rb
index ce922a4856..979ac0efcb 100644
--- a/spec/ruby/core/io/new_spec.rb
+++ b/spec/ruby/core/io/new_spec.rb
@@ -1,8 +1,16 @@
-require File.expand_path('../../../spec_helper', __FILE__)
-require File.expand_path('../shared/new', __FILE__)
+require_relative '../../spec_helper'
+require_relative 'shared/new'
+
+# NOTE: should be synchronized with library/stringio/initialize_spec.rb
 
 describe "IO.new" do
   it_behaves_like :io_new, :new
+
+  it "does not use the given block and warns to use IO::open" do
+    -> {
+      @io = IO.send(@method, @fd) { raise }
+    }.should complain(/warning: IO::new\(\) does not take block; use IO::open\(\) instead/)
+  end
 end
 
 describe "IO.new" do