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_testing.py

@@ -43,11 +43,11 @@ def path_contains(parent, child):
 
 
 class TestSpam(TestCase):
-    def test_filter(self):
+    def test_filter(self) -> None:
         self.assertEqual(0, spam.filter("spam"))
         self.assertNotEqual(0, spam.filter("ham"))
 
-    def test_virtualenv(self):
+    def test_virtualenv(self) -> None:
         # sys.prefix is different from sys.base_prefix when running a virtualenv
         # See https://docs.python.org/3/library/venv.html, which virtualenv seems
         # to honor in recent releases
@@ -58,7 +58,7 @@ class TestSpam(TestCase):
         self.assertTrue(path_contains(sys.prefix, spam.__file__))
         self.assertIn("VIRTUAL_ENV", os.environ)
 
-    def test_uname(self):
+    def test_uname(self) -> None:
         if platform.system() == "Windows":
             return
         # if we're running in 32-bit Python, check that the machine is i686.
@@ -69,7 +69,7 @@ class TestSpam(TestCase):
 '''
 
 
-def test(tmp_path):
+def test(tmp_path: Path) -> None:
     project_dir = tmp_path / "project"
     project_with_a_test.generate(project_dir)
 
@@ -90,7 +90,7 @@ def test(tmp_path):
     assert set(actual_wheels) == set(expected_wheels)
 
 
-def test_extras_require(tmp_path):
+def test_extras_require(tmp_path: Path) -> None:
     project_dir = tmp_path / "project"
     project_with_a_test.generate(project_dir)
 
@@ -112,7 +112,7 @@ def test_extras_require(tmp_path):
     assert set(actual_wheels) == set(expected_wheels)
 
 
-def test_dependency_groups(tmp_path):
+def test_dependency_groups(tmp_path: Path) -> None:
     group_project = project_with_a_test.copy()
     group_project.files["pyproject.toml"] = inspect.cleandoc("""
         [build-system]
@@ -149,12 +149,12 @@ project_with_a_failing_test.files["test/spam_test.py"] = r"""
 from unittest import TestCase
 
 class TestSpam(TestCase):
-    def test_something(self):
+    def test_something(self) -> None:
         self.fail('this test is supposed to fail')
 """
 
 
-def test_failing_test(tmp_path):
+def test_failing_test(tmp_path: Path) -> None:
     """Ensure a failing test causes cibuildwheel to error out and exit"""
     project_dir = tmp_path / "project"
     output_dir = tmp_path / "output"
@@ -215,7 +215,7 @@ def test_bare_pytest_invocation(
     )
 
 
-def test_test_sources(tmp_path):
+def test_test_sources(tmp_path: Path) -> None:
     project_dir = tmp_path / "project"
     project_with_a_test.generate(project_dir)
 
@@ -235,7 +235,7 @@ def test_test_sources(tmp_path):
     assert set(actual_wheels) == set(expected_wheels)
 
 
-def test_test_environment(tmp_path):
+def test_test_environment(tmp_path: Path) -> None:
     project_dir = tmp_path / "project"
     test_projects.new_c_project().generate(project_dir)