build: run mypy via tox

Tox now runs mypy on cloudevents itself, and the samples.

Signed-off-by: Hal Blackburn <hwtb2@cam.ac.uk>

requirements/dev.txt

@@ -5,3 +5,4 @@ pep8-naming
 flake8-print
 tox
 pre-commit
+mypy

requirements/mypy.txt

@@ -0,0 +1,5 @@
+mypy
+# mypy has the pydantic plugin enabled
+pydantic>=2.0.0,<3.0
+types-requests
+deprecation>=2.0,<3.0

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py{38,39,310,311,312},lint
+envlist = py{38,39,310,311,312},lint,mypy,mypy-samples-{image,json}
 skipsdist = True
 
 [testenv]
@@ -30,3 +30,21 @@ commands =
     black --check .
     isort -c cloudevents samples
     flake8 cloudevents samples --ignore W503,E731 --extend-ignore E203 --max-line-length 88
+
+[testenv:mypy]
+basepython = python3.11
+deps =
+    -r{toxinidir}/requirements/mypy.txt
+    # mypy needs test dependencies to check test modules
+    -r{toxinidir}/requirements/test.txt
+commands = mypy cloudevents
+
+[testenv:mypy-samples-{image,json}]
+basepython = python3.11
+setenv =
+    mypy-samples-image: SAMPLE_DIR={toxinidir}/samples/http-image-cloudevents
+    mypy-samples-json: SAMPLE_DIR={toxinidir}/samples/http-json-cloudevents
+deps =
+    -r{toxinidir}/requirements/mypy.txt
+    -r{env:SAMPLE_DIR}/requirements.txt
+commands = mypy {env:SAMPLE_DIR}