require File.expand_path('../../../spec_helper', __FILE__) ruby_version_is "2.3" do describe 'String#-@' do it 'returns self if the String is frozen' do input = 'foo'.freeze output = -input output.equal?(input).should == true output.frozen?.should == true end it 'returns a frozen copy if the String is not frozen' do input = 'foo' output = -input output.frozen?.should == true output.should == 'foo' end end end