diff --git a/internal/store/store_test.go b/internal/store/store_test.go
index 363abefc5..ff915181c 100644
--- a/internal/store/store_test.go
+++ b/internal/store/store_test.go
@@ -36,6 +36,7 @@ func makeTestExtCommit(height int64, timestamp time.Time) *types.ExtendedCommit
 			Timestamp:        timestamp,
 			Signature:        []byte("Signature"),
 		},
+		ExtensionSignature: []byte("ExtensionSignature"),
 	}}
 	return &types.ExtendedCommit{
 		Height: height,