run-length-encoding: Add simple edge cases

Author: behrtam

exercises/run-length-encoding/canonical-data.json

@@ -1,6 +1,6 @@
 {
    "#": [
-   	  "The tests deliberately check that single characters are encoded without count."
+      "The tests deliberately check that single characters are encoded without count."
    ],
    "cases": [
       {
@@ -29,14 +29,14 @@
         "expected": "zzz ZZ  zZ"
       },
       {
-        "description": "encode unicode",
-        "input": "⏰⚽⚽⚽⭐⭐⏰",
-        "expected": "⏰3⚽2⭐⏰"
+        "description": "nothing to encode",
+        "input": "XYZ",
+        "expected": "XYZ"
       },
       {
-        "description": "decode unicode",
-        "input": "⏰3⚽2⭐⏰",
-        "expected": "⏰⚽⚽⚽⭐⭐⏰"
+        "description": "nothing to decode",
+        "input": "",
+        "expected": ""
       }
    ]
 }