File: phpunit.xml

<?xml version="1.0" encoding="UTF-8"?>
<phpunit bootstrap="vendor/autoload.php" colors="true" backupGlobals="false"
         backupStaticAttributes="false" syntaxCheck="false">
    <testsuites>
        <testsuite name="Tests">
            <directory suffix="Test.php">tests</directory>
        </testsuite>
    </testsuites>
    <filter>
        <whitelist processUncoveredFilesFromWhitelist="false">
            <directory suffix=".php">src</directory>
        </whitelist>
    </filter>
</phpunit>