How to use application classes in a test?

Question

Yii

Available in the Yii2 basic project

"codeception/base": "^2.2.3",
        "codeception/verify": "~0.3.1",
        "codeception/specify": "~0.4.3"

Made a trial Unit test and when trying to create an object of any class
Similar errors
[Error] Class app\model\User not found