deps: add mock for tests.

Author: 2e0byo

poetry.lock

@@ -39,6 +39,7 @@ black = "^23.3.0"
 isort = "^5.12.0"
 ruff = "^0.0.277"
 docformatter = {extras = ["tomli"], version = "^1.7.3"}
+pytest-mock = "^3.11.1"
 
 [build-system]
 requires = ["poetry-core"]