+
+ open my $fh, '-|', qw(curl -sS), "$base/async-big" or die $!;
+ my $n = 0;
+ my $non_zero = 0;
+ while (1) {
+ my $r = sysread($fh, my $buf, 4096) or last;
+ $n += $r;
+ $buf =~ /\A\0+\z/ or $non_zero++;
+ }
+ is($n, 30 * 1024 * 1024, 'got expected output from curl');
+ is($non_zero, 0, 'read all zeros');