security/py-tuf: switch to USES=pytest, document failing tests

Reported by:	reprise
Approved by:	portmgr blanket

security/py-tuf/Makefile

@@ -16,14 +16,13 @@ LICENSE_FILE_MIT=	${WRKSRC}/LICENSE-MIT
 
 RUN_DEPENDS=	${PYTHON_PKGNAMEPREFIX}requests>=2.19.1:www/py-requests@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}securesystemslib>=0.22.0:security/py-securesystemslib@${PY_FLAVOR}
-TEST_DEPENDS=	${PYTHON_PKGNAMEPREFIX}pytest>0:devel/py-pytest@${PY_FLAVOR}
 
-USES=		python:3.7+
+USES=		python:3.7+ pytest
 USE_PYTHON=	autoplist concurrent distutils
 
 NO_ARCH=	yes
 
-do-test:
-	@cd ${WRKSRC}/tests && ${PYTHON_CMD} -m pytest -v -rs
+PYTEST_BROKEN_TESTS=	test_cleanup \
+			TestRepoExamples  # uses files missing from pypi distribution
 
 .include <bsd.port.mk>