Fix ordinal suffix logic and tests

Author: fatimarouchi

practice-tdd/get-ordinal-number.js

@@ -1,3 +1,23 @@
 export function getOrdinalNumber(num) {
-  return "1st";
+  const absNum = Math.abs(num);
+  const lastTwoDigits = absNum % 100;
+  const lastDigit = absNum % 10;
+
+  if (lastTwoDigits >= 11 && lastTwoDigits <= 13) {
+    return `${num}th`;
+  }
+
+  if (lastDigit === 1) {
+    return `${num}st`;
+  }
+
+  if (lastDigit === 2) {
+    return `${num}nd`;
+  }
+
+  if (lastDigit === 3) {
+    return `${num}rd`;
+  }
+
+  return `${num}th`;
 }