refactor: validate exact rank strings for numbers (reject '2.', '+2', etc.)

Author: Eugenie-A

Sprint-3/1-implement-and-rewrite-tests/implement/3-get-card-value.js

@@ -129,4 +129,15 @@ try {
 try {
   getCardValue("");
   console.error("Error was not thrown for empty string");
+} catch (e) {}
+
+// Invalid extra characters in rank
+try {
+  getCardValue("2.♠");
+  console.error("Should have thrown for '2.♠'");
+} catch (e) {}
+
+try {
+  getCardValue("+2♠");
+  console.error("Should have thrown for '+2♠'");
 } catch (e) {}