function testMakeBZ2SingleFile() {
// Silently skip bz2 test if bz2 is not installed.
exec('which bzip2', $output, $whichBzip2ErrorCode);
function testMakeBZ2SingleFile() {
// Silently skip bz2 test if bz2 is not installed.
exec('which bzip2', $output, $whichBzip2ErrorCode);