diff --git a/tests/config.nims b/tests/config.nims
index 690123c4a3..21cd327903 100644
--- a/tests/config.nims
+++ b/tests/config.nims
@@ -45,3 +45,4 @@ switch("define", "nimPreviewNonVarDestructor")
 switch("warningAserror", "UnnamedBreak")
 switch("legacy", "verboseTypeMismatch")
 switch("experimental", "vtables")
+switch("define", "nimSeqsV3")