diff --git a/exercises/luhn/canonical-data.json b/exercises/luhn/canonical-data.json
index 87e2c236a5..bc8180fa44 100644
--- a/exercises/luhn/canonical-data.json
+++ b/exercises/luhn/canonical-data.json
@@ -1,7 +1,12 @@
 {
   "valid": [
     {
-      "description": "single digit strings can not be valid",
+      "description": "zero length strings are not valid",
+      "input": "",
+      "expected": false
+    },
+    {
+      "description": "single digit strings are not valid",
       "input": "1",
       "expected": false
     },