README example produces empty HTML report

[still-dreaming-1]

| php-code-coverage version | 5.2.2
| PHP version | 7.1.8
| Driver | Xdebug
| Xdebug version (if used) | 2.5.5
| Installation Method | Composer
| Usage Method | other

I'm just trying to get code coverage working for the simplest possible case. I tried copying and pasting the code from the README page into a file and then running the file from php. Of course I also initialized an instance of a local class and called one of the methods. I'm not finding any errors, and the reports are produced, but they don't show anything being covered or missed. In the HTML report, in the Code Coverage table, it just shows everything as n/a or 0/0.

[still-dreaming-1]

I figured it out. It only reports on whitelisted files and directories. I recommend adding an example to the REAME sample code showing how to whitelist a directory.