diff --git a/Makefile.pre.in b/Makefile.pre.in
index e7f8abce43d648..5d8be3655fef04 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -2194,6 +2194,7 @@ TESTSUBDIRS=	idlelib/idle_test \
 		test/leakers \
 		test/libregrtest \
 		test/mathdata \
+		test/regrtestdata \
 		test/subprocessdata \
 		test/support \
 		test/support/_hypothesis_stubs \