diff --git a/pytest.ini b/pytest.ini
deleted file mode 100644
index 529a96a81c76e6d2607e1cddcc79024981d3cc56..0000000000000000000000000000000000000000
--- a/pytest.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[pytest]
-markers =
-    local_server: mark a test as requiring a local caosdb server
-    slow: mark a test as slow (execution regularly takes 5s or longer)
diff --git a/tox.ini b/tox.ini
index 2b326539ffb4c129bbda8705b341148e92960a14..c86b7e505e1cce056b9e20faeba993c1511d8667 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,3 +17,9 @@ commands_pre=pip install ../caosdb-pylib/
     python -c "import caosdb; print(caosdb.version.version)"
 # Add "-x" to stop at first error.
 commands=pytest --cov=caosdb -vv {posargs}
+
+[pytest]
+markers =
+    local_server: mark a test as requiring a local caosdb server
+    slow: mark a test as slow (execution regularly takes 5s or longer)
+xfail_strict = True