output_is     { hello() } "hello world\n", STDOUT, "hello world";
  output_isnt   { hello() } "goodbye",       STDOUT, "not goodbye";
  output_unlike { hello() } qr/bye/,         STDOUT, "didn't print bye";
  output_like   { hello() } qr/hello/,       STDOUT, "printed hello";
  like(Test::Output->last, qr/world/, "... and world");