minitest not capturing IO

Dir.pwd

require 'singleton'

class TestIO
    include Singleton

    self.instance

    def self.pwd
      puts Dir.pwd
    end
    
    def self.pwd_works
      Dir.pwd
    end
end

require 'minitest/autorun'

describe TestIO do
   
   describe "when we request current working dir" do
     it "must return the current working dir" do
        expected = Dir.pwd
        actual = TestIO.pwd
        assert_output(expected) { print actual }
      end
   end
   
   describe "when we request current working dir" do
     it "must return the current working dir" do
        expected = Dir.pwd
        actual = TestIO.pwd_works
        assert_output(expected) { print actual }
      end
   end

end