Error when running PHPunit

[Michael Born]

When attempting to use the locally installed (and super old) phpunit 3.7.5 via running ./vendor/bin/phpunit, I get the following:

$ ./vendor/bin/phpunit
PHP Fatal error:  Uncaught Error: Class 'File_Iterator_Facade' not found in /home/me/etsy-php/vendor/phpunit/phpunit/PHPUnit/Util/Configuration.php:813
Stack trace:
#0 /home/me/etsy-php/vendor/phpunit/phpunit/PHPUnit/Util/Configuration.php(776): PHPUnit_Util_Configuration->getTestSuite(Object(DOMElement), NULL)
#1 /home/me/etsy-php/vendor/phpunit/phpunit/PHPUnit/TextUI/Command.php(657): PHPUnit_Util_Configuration->getTestSuiteConfiguration(NULL)
#2 /home/me/etsy-php/vendor/phpunit/phpunit/PHPUnit/TextUI/Command.php(138): PHPUnit_TextUI_Command->handleArguments(Array)
#3 /home/me/etsy-php/vendor/phpunit/phpunit/PHPUnit/TextUI/Command.php(129): PHPUnit_TextUI_Command->run(Array, true)
#4 /home/me/etsy-php/vendor/phpunit/phpunit/composer/bin/phpunit(42): PHPUnit_TextUI_Command::main()
#5 {main}
  thrown in /home/me/etsy-php/vendor/phpunit/phpunit/PHPUnit/Util/Configuration.php on line 813

When I install phpunit globally via sudo apt install phpunit, I get PHPunit 6.5 and running phpunit shows:

$ phpunit
PHPUnit 6.5.5 by Sebastian Bergmann and contributors.

Time: 21 ms, Memory: 4.00MB

No tests executed!

I think PHPunit needs to be upgraded. PR coming! :)