老师，我在本节前面讲的执行 phpunit 命令时报如下错误，无法解决

➜ laravel-bbs git:(api) phpunit

Fatal error: Uncaught PHPUnit_Framework_Exception: Neither ".php" nor ".php" could be opened. in /Applications/XAMPP/xamppfiles/lib/php/PHPUnit/Util/Skeleton/Test.php on line 100

PHPUnit_Framework_Exception: Neither ".php" nor ".php" could be opened. in /Applications/XAMPP/xamppfiles/lib/php/PHPUnit/Util/Skeleton/Test.php on line 100

Call Stack:
0.0036 355864 1. {main}() /Applications/XAMPP/xamppfiles/bin/phpunit:0
0.0194 562784 2. PHPUnit_TextUI_Command::main() /Applications/XAMPP/xamppfiles/bin/phpunit:46
0.0194 562880 3. PHPUnit_TextUI_Command->run() /Applications/XAMPP/xamppfiles/lib/php/PHPUnit/TextUI/Command.php:126
0.0965 5166192 4. PHPUnit_Util_Skeleton_Test->__construct() /Applications/XAMPP/xamppfiles/lib/php/PHPUnit/TextUI/Command.php:152