test.p6

use Test;

class IO::Captured is IO::Handle {
    has @.w;
    method say (*@w) {
        @.w.push: @w.join: ""
    };
    method Str {@.w.join: ""}
};

sub output-capture (&code) {
    my $capture = IO::Captured.new;
    my $saved-out = $PROCESS::OUT;
    my $saved-err = $PROCESS::ERR;

    $PROCESS::OUT = $capture;
    $PROCESS::ERR = $capture;

    &code();

    $PROCESS::OUT = $saved-out;
    $PROCESS::ERR = $saved-err;

    return $capture.Str;
};

#is 1, 1;

my $x = output-capture { EVAL "use Test; is 1, 2; done-testing" };
say "Captured [[$x]]";