diff --git a/pytest.ini b/pytest.ini
index e86f7f4..c8e8c19 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -1,3 +1,5 @@
 [pytest]
 addopts = --doctest-modules
 norecursedirs = docs
+markers =
+    fs: tests that involve filesystem ios