diff --git a/tox.ini b/tox.ini
index 8212226eef2759c1864a86b8a3ad8f926480db4a..10f495064fac42a6f3c60155ba64541952078c4e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,3 +17,5 @@ max-line-length=100
 testpaths = unittests
 xfail_strict = True
 addopts = -x -vv --cov=caosdb
+pythonpath = src
+