tests: fully type the test suite (#2794)

* tests: fully type the test suite

* chore: require more typing

Signed-off-by: Henry Schreiner <henryfs@princeton.edu>

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Signed-off-by: Henry Schreiner <henryfs@princeton.edu>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

test/test_container_images.py

@@ -1,5 +1,6 @@
 import platform
 import textwrap
+from pathlib import Path
 
 import pytest
 
@@ -22,7 +23,7 @@ dockcross_only_project = test_projects.new_c_project(
 
 
 @pytest.mark.usefixtures("docker_cleanup")
-def test(tmp_path):
+def test(tmp_path: Path) -> None:
     if utils.get_platform() != "linux":
         pytest.skip("the test is only relevant to the linux build")
     if platform.machine() not in ["x86_64", "i686"]: