Fix PHP Warning: chdir(): Not a directory (errno 20) in /hoge/mpunit/bin/mpunit on line 24 #17

 ✗ ./bin/mpunit example/tests/FizzBuzzParameterizedTest.php
Mini PHP xUnit Testing.

PHP Warning:  chdir(): Not a directory (errno 20) in /hoge/mpunit/bin/mpunit on line 24

Warning: chdir(): Not a directory (errno 20) in /hoge/mpunit/bin/mpunit on line 24