diff --git a/contrib/python3-whitelist b/contrib/python3-whitelist
--- a/contrib/python3-whitelist
+++ b/contrib/python3-whitelist
@@ -116,6 +116,7 @@
 test-copy-move-merge.t
 test-copy.t
 test-copytrace-heuristics.t
+test-custom-filters.t
 test-debugbuilddag.t
 test-debugbundle.t
 test-debugcommands.t
diff --git a/tests/test-custom-filters.t b/tests/test-custom-filters.t
--- a/tests/test-custom-filters.t
+++ b/tests/test-custom-filters.t
@@ -27,6 +27,7 @@
   > .hgignore
   > prefix.py
   > prefix.pyc
+  > __pycache__/
   > EOF
 
   $ cat > stuff.txt <<EOF