NonPrintableCharacterFixer - fix for backslash and quotes when changing to escape sequences

[kubawerlos]

Fixes #4663 and replaces #4664.

Ping @mvorisek as reporter and @ivan1986 as the original author for review.

[mvorisek]

For me it seems like it does not handle backslashes correctly:

$content = "'\\\\\\\\'";
var_dump($content);

$content = str_replace("\\'", "'", $content);
$content = preg_replace('/([\\\\$])/', '\\\\$1', $content);
var_dump($content);

To replace escaped quotes (and not preceded by double/escaped backslash) you needs something like this: https://github.com/FriendsOfPHP/PHP-CS-Fixer/pull/4664/files#diff-778a67f6227ed439e1490963b2f0f94dR154

[ivan1986]

Yes, need add tests

            [
                <<<'EXPECTED'
<?php echo "\\\u{200b}\"";
EXPECTED
                ,
                sprintf(<<<'INPUT'
<?php echo '\\%s"';
INPUT
                 , pack('H*', 'e2808b')),
            ],
            [
                <<<'EXPECTED'
<?php echo "\\\u{200b}'";
EXPECTED
                ,
                sprintf(<<<'INPUT'
<?php echo '\\%s\'';
INPUT
                 , pack('H*', 'e2808b')),
            ],

for check double slashes, it's fail now, or add slashes into exist tests

[kubawerlos]

For me it seems

@mvorisek take an example from @ivan1986 - presenting test case is much more valuable.

@ivan1986 added yours 2 - thanks - and few more for backslashes.

[julienfalque]

Thank you @kubawerlos.