Tests munging with a null byte in the filename.
function testMungeNullByte() {
$prefix = $this
->randomName();
$filename = $prefix . '.' . $this->bad_extension . "\0.txt";
$this
->assertEqual(file_munge_filename($filename, ''), $prefix . '.' . $this->bad_extension . '_.txt', 'A filename with a null byte is correctly munged to remove the null byte.');
}