dev-python/mistletoe: fix python tests

Closes: https://bugs.gentoo.org/888745

Signed-off-by: Julien Roy <julien@jroy.ca>

dev-python/mistletoe/mistletoe-0.9.0.ebuild

@@ -1,4 +1,4 @@
-# Copyright 2022 Gentoo Authors
+# Copyright 2022-2023 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 EAPI=8
@@ -17,3 +17,5 @@ KEYWORDS="~amd64"
 
 RDEPEND=""
 DEPEND="${RDEPEND}"
+
+distutils_enable_tests unittest