Enable type-checking

Author: jwodder

.github/workflows/test.yml

@@ -34,6 +34,8 @@ jobs:
         include:
           - python-version: '3.7'
             toxenv: lint
+          - python-version: '3.7'
+            toxenv: typing
     steps:
       - name: Check out repository
         uses: actions/checkout@v4

setup.cfg

@@ -34,16 +34,36 @@ classifiers =
     Environment :: Console
     Intended Audience :: Developers
     Topic :: System :: Logging
+    Typing :: Typed
 
 project_urls =
     Source Code = https://github.com/jwodder/click-loglevel
     Bug Tracker = https://github.com/jwodder/click-loglevel/issues
 
 [options]
-py_modules = click_loglevel
+packages = find_namespace:
 package_dir =
     =src
 include_package_data = True
 python_requires = >=3.7
 install_requires =
     click >= 8.0
+
+[options.packages.find]
+where = src
+
+[mypy]
+allow_incomplete_defs = False
+allow_untyped_defs = False
+ignore_missing_imports = True
+# <https://github.com/python/mypy/issues/7773>:
+no_implicit_optional = True
+implicit_reexport = False
+local_partial_types = True
+pretty = True
+show_error_codes = True
+show_traceback = True
+strict_equality = True
+warn_redundant_casts = True
+warn_return_any = True
+warn_unreachable = True

src/click_loglevel.py renamed to src/click_loglevel/__init__.py

@@ -1,5 +1,5 @@
 [tox]
-envlist = lint,py{36,37,38,39,310,311,312,py3}-click8
+envlist = lint,typing,py{36,37,38,39,310,311,312,py3}-click8
 skip_missing_interpreters = True
 isolated_build = True
 minversion = 3.3.0
@@ -22,6 +22,13 @@ deps =
 commands =
     flake8 src test
 
+[testenv:typing]
+deps =
+    mypy
+    {[testenv]deps}
+commands =
+    mypy src test
+
 [pytest]
 addopts = --cov=click_loglevel --no-cov-on-fail
 filterwarnings = error