1 files changed, 8 insertions, 3 deletions
diff --git a/spec/ruby/core/class/dup_spec.rb b/spec/ruby/core/class/dup_spec.rb
index 0548536bd6..17c0171ceb 100644
--- a/spec/ruby/core/class/dup_spec.rb
+++ b/spec/ruby/core/class/dup_spec.rb
@@ -1,5 +1,5 @@
-require File.expand_path('../../../spec_helper', __FILE__)
-require File.expand_path('../fixtures/classes', __FILE__)
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 # NOTE: This is actually implemented by Module#initialize_copy
 describe "Class#dup" do
@@ -53,12 +53,17 @@ describe "Class#dup" do
 
   it "sets the name from the class to nil if not assigned to a constant" do
     copy = CoreClassSpecs::Record.dup
-    copy.name.should be_nil
+    copy.name.should == nil
   end
 
   it "stores the new name if assigned to a constant" do
     CoreClassSpecs::RecordCopy = CoreClassSpecs::Record.dup
     CoreClassSpecs::RecordCopy.name.should == "CoreClassSpecs::RecordCopy"
+  ensure
+    CoreClassSpecs.send(:remove_const, :RecordCopy)
   end
 
+  it "raises TypeError if called on BasicObject" do
+    -> { BasicObject.dup }.should.raise(TypeError, "can't copy the root class")
+  end
 end