Custom Theme registration.php error in Magento 2

Question

I'm using magento 2.2.5 and try to create customer theme, I added the registration.php inside app/design/frontend/Test/mine/

<?php
\Magento\Framework\Component\ComponentRegistrar::register(
  \Magento\Framework\Component\ComponentRegistrar::THEME,
  'frontend/Test/mine',
  __DIR__
);

when I ran the php bin/magento setup:upgrade , I got the following error:

PHP Parse error: syntax error, unexpected ''frontend/Test/mine'' (T_CONSTANT_ENCAPSED_STRING), expecting ',' or ')' in /var/www/project/app/design/frontend/Test/mine/registration.php on line 4

Answer 1

I cannot explain this, but the error was fixed by just rearranging the elements in one line like this:

<?php \Magento\Framework\Component\ComponentRegistrar::register( \Magento\Framework\Component\ComponentRegistrar::THEME, 'frontend/Test/mine', __DIR__ );

Reference here

Answer 2

Your component name should be in the format Vendor_Module, so in your case that would be Mine_Theme instead of frontend/Test/mine.