diff --git a/make/py-topdir.mk b/make/py-topdir.mk
index c6b0f3ac..75d95b50 100644
--- a/make/py-topdir.mk
+++ b/make/py-topdir.mk
@@ -9,6 +9,9 @@ MYPY_PATH_DIRECTIVE          = mypy_path = "$(MYPY_CONFIG_PATH)"
 
 ifndef PY_CHECK_ROOTS
   PY_CHECK_ROOTS             = $(wildcard $(TOPDIR)/src $(TOPDIR)/tools)
+  ifneq ($(wildcard dirs-all.done),)
+    PY_CHECK_ROOTS          += $(wildcard $(TOPDIR)/test)
+  endif
 endif
 
 all: