Phpunit testing and using extensions in php?

Question

Yii

Hello!
The question arose, let's say I installed an extension on PHP (as an example of gnupg).
I'm trying to write a test in yii1 for encrypting-decrypting text.
But phpunit swears it says the gnupg.php file was not found, although there is no such file, because just the extension is installed.
Swears at the call: In Yii itself, the code works and does not require file uploads. Naturally, the tests themselves and the class are inherited from the Yii TestCase wrappers.
$pgp = new gnupg();