diff --git a/src/conftest.py b/src/conftest.py
index b507141..6f46277 100644
--- a/src/conftest.py
+++ b/src/conftest.py
@@ -41,14 +41,17 @@ def pytest_addoption(parser):
 @pytest.fixture(scope="session", autouse=True)
 def dirmanager(request) -> DirManager:
     tests_dir = request.config.getoption("--tests_dir")
+    assert tests_dir is not None, "required pytest command line argument not given"
     tests_dir = Path(tests_dir)
     session_id = request.config.getoption("--session_id")
+    assert session_id is not None, "required pytest command line argument not given"
     return DirManager(tests_dir=tests_dir, session_id=session_id)
 
 
 @pytest.fixture(scope="session", autouse=True)
 def dotenv_config(request) -> dict[str, str]:
     dotenv_path = request.config.getoption("--env_file")
+    assert dotenv_path is not None, "required pytest command line argument not given"
     dotenv_path = Path(dotenv_path)
     assert dotenv_path.is_file()
     return dotenv_values(dotenv_path)