diff --git a/tests/test-check-module-imports.t b/tests/test-check-module-imports.t
index 99615755fb8e6ae68ac3d13d3a536b3ae39e299a_dGVzdHMvdGVzdC1jaGVjay1tb2R1bGUtaW1wb3J0cy50..662b08ac9869b93a95657e753542373a81c1ec25_dGVzdHMvdGVzdC1jaGVjay1tb2R1bGUtaW1wb3J0cy50 100644
--- a/tests/test-check-module-imports.t
+++ b/tests/test-check-module-imports.t
@@ -43,3 +43,10 @@
   > -X tests/test-verify-repo-operations.py \
   > -X tests/test-extension.t \
   > | sed 's-\\-/-g' | "$PYTHON" "$import_checker" -
+
+All files that get type checked must have 'from __future__ import annotations'
+
+  $ testrepohg files 'set:**.py and size(">0")' -I mercurial -I hgext -X mercurial/thirdparty -0 \
+  > | xargs -0 grep -L '^from __future__ import annotations$'
+  mercurial/cmd_impls/graft.py
+  mercurial/testing/ps_util.py