add get ordinal number tests and function

Author: tomdu3

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

@@ -1,5 +1,20 @@
 function getOrdinalNumber(num) {
-  return "1st";
+  // check if the input is not a number, not an integer, or if it's negative
+  if (typeof num !== "number" || !Number.isInteger(num) || num < 0) {
+    throw new Error("Invalid input: number must be a non-negative integer");
+  }
+
+if (num % 100 >= 11 && num % 100 <= 13) {  // check for numbers ending with 11, 12, or 13
+    return num + "th";
+  } else if (num % 10 === 1) {  // check for numbers ending with 1 (but not 11)
+    return num + "st";
+  } else if (num % 10 === 2) {  // check for numbers ending with 2 (but not 12)
+    return num + "nd";
+  } else if (num % 10 === 3) {  // check for numbers ending with 3 (but not 13)
+    return num + "rd";
+  }
+  // For all other numbers, append "th"
+  return num + "th";
 }
 
 module.exports = getOrdinalNumber;

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

@@ -18,3 +18,68 @@ test("should append 'st' for numbers ending with 1, except those ending with 11"
   expect(getOrdinalNumber(21)).toEqual("21st");
   expect(getOrdinalNumber(131)).toEqual("131st");
 });
+
+// Case 2: Numbers ending with 2 (but not 12)
+// When the number ends with 2, except those ending with 12,
+// Then the function should return a string by appending "nd" to the number.
+test("should append 'nd' for numbers ending with 2, except those ending with 12", () => {
+  expect(getOrdinalNumber(2)).toEqual("2nd");
+  expect(getOrdinalNumber(22)).toEqual("22nd");
+  expect(getOrdinalNumber(132)).toEqual("132nd");
+});
+
+// Case 3: Numbers ending with 3 (but not 13)
+// When the number ends with 3, except those ending with 13,
+// Then the function should return a string by appending "rd" to the number.
+test("should append 'rd' for numbers ending with 3, except those ending with 13", () => {
+  expect(getOrdinalNumber(3)).toEqual("3rd");
+  expect(getOrdinalNumber(23)).toEqual("23rd");
+  expect(getOrdinalNumber(133)).toEqual("133rd");
+});
+
+// Case 4: Numbers ending with 11, 12, or 13
+// When the number ends with 11, 12, or 13,
+// Then the function should return a string by appending "th" to the number.
+test("should append 'th' for numbers ending with 11, 12, or 13", () => {
+  expect(getOrdinalNumber(11)).toEqual("11th");
+  expect(getOrdinalNumber(12)).toEqual("12th");
+  expect(getOrdinalNumber(13)).toEqual("13th");
+});
+
+// Case 5: All other numbers
+// When the number does not fall into any of the above categories,
+// Then the function should return a string by appending "th" to the number.
+test("should append 'th' for all other numbers", () => {
+  expect(getOrdinalNumber(4)).toEqual("4th");
+  expect(getOrdinalNumber(5)).toEqual("5th");
+  expect(getOrdinalNumber(6)).toEqual("6th");
+  expect(getOrdinalNumber(7)).toEqual("7th");
+  expect(getOrdinalNumber(8)).toEqual("8th");
+  expect(getOrdinalNumber(9)).toEqual("9th");
+  expect(getOrdinalNumber(10)).toEqual("10th");
+  expect(getOrdinalNumber(127)).toEqual("127th");
+});
+
+// Case 6: Negative numbers
+// When the number is negative,
+// Then the function should throw an error, as negative numbers are not valid inputs.
+test("should throw an error for negative numbers", () => {
+  expect(() => getOrdinalNumber(-1)).toThrow("Invalid input: number must be a non-negative integer");
+  expect(() => getOrdinalNumber(-22)).toThrow("Invalid input: number must be a non-negative integer");
+});
+
+// Case 7: Non-integer numbers
+// When the number is not an integer (e.g., a float),
+// Then the function should throw an error, as only non-negative integers are valid inputs.
+test("should throw an error for non-integer numbers", () => {
+  expect(() => getOrdinalNumber(1.5)).toThrow("Invalid input: number must be a non-negative integer");
+  expect(() => getOrdinalNumber(2.7)).toThrow("Invalid input: number must be a non-negative integer");
+});
+
+// Case 8: Non-number inputs
+// When the input is not a number (e.g., a string, object, or array),
+// Then the function should throw an error, as only non-negative integers are valid inputs.
+test("should throw an error for non-number inputs", () => {
+  expect(() => getOrdinalNumber("1")).toThrow("Invalid input: number must be a non-negative integer");
+  expect(() => getOrdinalNumber("abcd")).toThrow("Invalid input: number must be a non-negative integer");
+});