https://github.com/okken/pytest-check/issues/212

--- pytest_check-3.0.3/tox.ini.orig
+++ pytest_check-3.0.3/tox.ini
@@ -31,6 +31,8 @@
 skip_missing_interpreters = true
 
 [testenv]
+deps =
+    pytest-run-parallel
 commands = pytest {posargs}
 description = Run pytest
 package = wheel