Add typecheck

nox_report.py

@@ -2,7 +2,7 @@
 import json
 
 
-def parse_report(report_file, title):
+def parse_report(report_file: str, title: str) -> None:
     with open(report_file, 'r') as fh:
         report = json.load(fh)
 

noxfile.py

@@ -1,3 +1,4 @@
+# mypy: disallow-untyped-defs=False, check_untyped_defs=True
 import nox
 
 
@@ -8,6 +9,13 @@ def lint(session):
     session.run('flake8', '--statistics', '.')
 
 
+@nox.session
+def typecheck(session):
+    """Typecheck using MyPy."""
+    session.install('mypy', 'pytest', 'nox')
+    session.run('mypy', '--strict', '.')
+
+
 @nox.session(python=['3.11', '3.12', '3.13'])
 def test(session):
     """Run tests."""

test_nox_report.py

@@ -5,11 +5,12 @@
 
 
 @pytest.fixture
-def sample_report():
+def sample_report() -> Path:
     return Path(__file__).parent / 'sample_report.json'
 
 
-def test_output(capsys, sample_report):
+def test_output(
+        capsys: pytest.CaptureFixture[str], sample_report: Path) -> None:
     nox_report.parse_report(str(sample_report), 'Nox test')
     out, _ = capsys.readouterr()
     assert out == textwrap.dedent(