WIP

tox.ini

diff --git a/tox.ini b/tox.ini
index 7282f97..bda929b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,6 +11,7 @@
 deps =
     Cython
     codecov
+    coverage
 commands =
     pytest --cov --cov-append
     codecov