phpunit.xml配置之后，总是“No tests executed”

The filenames must end with "Test.php". This is what PHPUnit is looking for within directories.

其实这是默认情况，但可以指定文件后缀的（suffix），具体是写在directory后面，例如这样的：

<?xml version="1.0" encoding="UTF-8"?>
<phpunit bootstrap="vendor/autoload.php"
    colors="true"
    verbose="true"
    stopOnFailure="false">
    <testsuites>
        <testsuite name="Doraemon Test">
            <directory suffix="Tests.php">tests</directory>
        </testsuite>
    </testsuites>
</phpunit>