Refactor tests in getOrdinalNumber to cover additional cases and improve error handling

Author: MohammedNaru

Sprint-3/2-practice-tdd/get-ordinal-number.test.js

@@ -1,13 +1,55 @@
 const getOrdinalNumber = require("./get-ordinal-number");
-// In this week's prep, we started implementing getOrdinalNumber
 
-// continue testing and implementing getOrdinalNumber for additional cases
-// Write your tests using Jest - remember to run your tests often for continual feedback
+// Category 1: Numbers ending in 11, 12, 13 → always "th"
+test("appends 'th' to numbers ending in 11, 12, or 13", () => {
+  const numbers = [11, 12, 13, 111, 1012, 1313];
+  numbers.forEach(num => {
+    expect(getOrdinalNumber(num)).toEqual(`${num}th`);
+  });
+});
+
+// Category 2: Numbers ending in 1 → "st" (except those ending in 11)
+test("appends 'st' to numbers ending in 1 except those ending in 11", () => {
+  const numbers = [1, 21, 101, 1001];
+  numbers.forEach(num => {
+    expect(getOrdinalNumber(num)).toEqual(`${num}st`);
+  });
+});
 
-// Case 1: Identify the ordinal number for 1
-// When the number is 1,
-// Then the function should return "1st"
+// Category 3: Numbers ending in 2 → "nd" (except those ending in 12)
+test("appends 'nd' to numbers ending in 2 except those ending in 12", () => {
+  const numbers = [2, 22, 102, 202];
+  numbers.forEach(num => {
+    expect(getOrdinalNumber(num)).toEqual(`${num}nd`);
+  });
+});
+
+// Category 4: Numbers ending in 3 → "rd" (except those ending in 13)
+test("appends 'rd' to numbers ending in 3 except those ending in 13", () => {
+  const numbers = [3, 23, 103, 1003];
+  numbers.forEach(num => {
+    expect(getOrdinalNumber(num)).toEqual(`${num}rd`);
+  });
+});
+
+// Category 5: All other numbers → "th"
+test("appends 'th' to numbers that don't meet special suffix rules", () => {
+  const numbers = [4, 5, 6, 9, 20, 100, 1004, 1009];
+  numbers.forEach(num => {
+    expect(getOrdinalNumber(num)).toEqual(`${num}th`);
+  });
+});
+
+// Error handling - Non-integers
+test("throws an error when number is not an integer", () => {
+  const invalidInputs = [1.5, "3", null, undefined, {}, [], NaN];
+
+  invalidInputs.forEach(input => {
+    expect(() => getOrdinalNumber(input)).toThrow("Input must be an integer");
+  });
+});
 
-test("should return '1st' for 1", () => {
-  expect(getOrdinalNumber(1)).toEqual("1st");
+// Error handling - Negative values
+test("throws an error when number is negative", () => {
+  expect(() => getOrdinalNumber(-1)).toThrow("Input must be a non-negative integer");
 });