Glasgow | 25-ITP-SEP | Mohammed Abdoon | Sprint 3 | Coursework/2-practice-tdd #746

M-Abdoon · 2025-10-10T16:25:51Z

Learners, PR Template

Self checklist

I have titled my PR with Region | Cohort | FirstName LastName | Sprint | Assignment Title
My changes meet the requirements of the task
I have tested my changes
My changes follow the style guide

Changelist

I modified the function countChar() so it can find a character withing a string and returns its occurrence times if it exists.
also the function getOrdinalNumber() to return "1st" when the input is 1 or 0 when the input number is not 1.
also modified the function repeat() to repeat the str count times, and returns string error if count is negative.
the test files are also updated with the new test cases.

Questions

No questions.

cjyuan · 2025-10-18T14:06:55Z

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

The function should work for any positive integers.

Can you lookup the rules for representing ordinal numbers?

You should prepare tests in get-ordinal-number.test.js file first before implementing getOrdinalNumber().

For example, we can prepare a test for numbers 2, 22, 132, etc. as

test("append 'nd' to numbers ending in 2, except those ending in 12", () => { expect( getOrdinalNumber(2) ).toEqual("2nd"); expect( getOrdinalNumber(22) ).toEqual("22nd"); expect( getOrdinalNumber(132) ).toEqual("132nd"); });

Thank you for the feedback. I set the tests for the function and modified the function getOrdinalNumber() to meet the requirements and to handle all possible cases.

cjyuan · 2025-10-18T14:13:07Z

Sprint-3/2-practice-tdd/repeat.js

+  if(count < 0) {
+    return "Error: Negative counts are not valid.";
+  }


How would the caller distinguish the result of the following two function calls?

repeat("Error: Negative counts are not valid.", 1)

repeat("", -1)

Both function calls return the same value.

Oh yes, the result will be the same, I should have used throw error to handle the invalid inputs.
I modified it to be as follows:

if (typeof count !== "number" || isNaN(count) || count < 0) { throw new Error("Count must be a valid number"); }

cjyuan · 2025-10-18T14:13:58Z

Sprint-3/2-practice-tdd/repeat.test.js

+test("should repeat the string 0 times ( means the output will be an empty string)", () => {
+  const str = "hello";
+  const count = -3;
+  const repeatedStr = repeat(str, count);
+  expect(repeatedStr).toEqual("Error: Negative counts are not valid.");
+});


If you modified repeat() to throw an error when count is negative, and you wanted to test if the function can throw an error as expected, you can use .toThrow(). You can find out more about how to use .toThrow() here: https://jestjs.io/docs/expect#tothrowerror (Note: Pay close attention to the syntax of the example)

I see, I didn't know that I could also test functions using .toThrow. thank you for letting me know, I changed the code so it can check if the function throws an error when passing invalid inputs

M-Abdoon · 2025-10-19T13:04:28Z

I made changes to the code and fixed the mistakes.

cjyuan

Changes look good. I have some follow-ups.

cjyuan · 2025-10-19T14:52:28Z

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

-    return "1st";
-  return 0;
+  //
+  if (typeof num !== "number" || !Number.isInteger(num) || num <= 0) {


This condition can be shorten. Can you figure out how?

Yes, I think I one of these conditions typeof num !== "number" || !Number.isInteger(num) is not needed since they both check if the input is a valid number.

typeof num !== "number" and !Number.isInteger(num) are not equivalent. One of them is stricter than the other.

Both Infinity and NaN can still pass this check: typeof num !== "number".

Yes, that's right. They are not equivalent. I tested them and learned that Infinity and NaN are actually type of numbers, that's why the rule typeof num !== "number" won't work here. So the best practice is to use Number.isInteger(), as this method excludes both NaN and Infinity.
I updated the function and added new test cases including NaN, Infinity, strings and arrays and instead of showing a string error message, I used throw an error with an error message

cjyuan · 2025-10-19T15:28:28Z

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

+// Case 3: Identify the ordinal numbers for 3 to 12
+test("should return correct ordinal suffixes for numbers 3 to 12", () => {
+    expect( getOrdinalNumber(3) ).toEqual("3rd");
+    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(11) ).toEqual("11th");
+    expect( getOrdinalNumber(12) ).toEqual("12th");
+});
+// Case 4: Identify the ordinal numbers for numbers above 12
+test("should return correct ordinal suffixes for numbers above 12", () => {
+    expect( getOrdinalNumber(13) ).toEqual("13th");
+    expect( getOrdinalNumber(19) ).toEqual("19th");
+    expect( getOrdinalNumber(23) ).toEqual("23rd");
+    expect( getOrdinalNumber(34) ).toEqual("34th");
+    expect( getOrdinalNumber(45) ).toEqual("45th");
+    expect( getOrdinalNumber(56) ).toEqual("56th");
+    expect( getOrdinalNumber(67) ).toEqual("67th");
+});
+
+// Case 5: Identify the ordinal numbers for numbers like 20 30 40 etc
+test("should return correct ordinal suffixes for multiples of ten", () => {
+    expect( getOrdinalNumber(20) ).toEqual("20th");
+    expect( getOrdinalNumber(30) ).toEqual("30th");
+    expect( getOrdinalNumber(70) ).toEqual("70th");
+    expect( getOrdinalNumber(50) ).toEqual("50th");
+});
+
+// Case 6: dealing with big numbers
+test("should return correct ordinal suffixes for big numbers", () => {
+    expect( getOrdinalNumber(111) ).toEqual("111th");
+    expect( getOrdinalNumber(4712) ).toEqual("4712th");
+    expect( getOrdinalNumber(10003) ).toEqual("10003rd");
+    expect( getOrdinalNumber(10012) ).toEqual("10012th");
+});


Why categorize the input number into 3-12, and >12? Why choose 12 as the cutting point?
Why do multiples of 10 need a separate category?

They way the possible input values are being categorized seem a bit illogical.

The categories (3–12, >12, multiples of 10) are not part of the logic itself, they’re just for organizing the test cases.

I grouped them that way to make sure the function covered different patterns

3 - 10 is for testing numbers that only consist of 1 number, maybe I should have categorized them from 0 to 9.

11 and 12 are special exceptions (11th, 12th), when the last number is 1 or 2 it will always be "st" and "nd" except for these cases.

Multiples of 10 are a separate group just to confirm that round numbers still get “th”.

It’s not about logic segmentation, just clearer test coverage.

Ideally, the test description should help a developer determine which cases the function needs to handle.
When a test fails, the description should also help the developer identify which case the function missed.

While your categories do cover all numbers, here’s another way to categorize the input (for your reference):

Numbers that end with "st"

Numbers that end with "nd"

Numbers that end with "rd"

Numbers that end with "th"

Numbers whose last two digits are in the range 11–13 (special cases)

Thanks a lot for the explanation and for clearing things up! I’ve re-categorized the test cases like you suggested.

cjyuan · 2025-10-19T15:29:57Z

Sprint-3/2-practice-tdd/repeat.js

 function repeat(str, count) {
-  if(count < 0) {
-    return "Error: Negative counts are not valid.";
+  if (typeof count !== "number" || isNaN(count) || count < 0) {


Can count be 0.5 or Infinity?

if count is 0.5, the function will treat it as 0, so an empty string will be returned.
If count is Infinity, the function will throw a RangeError because a string cannot be repeated infinitely.

Why define a condition that rejects NaN but not Infinity?

I didn't know what really the difference was. but I changed the rule and used Number.isInteger() instead of isNaN.
Number.isInteger() is more general and can detect both NaN and Infinity.

If you have time, look up the characteristics of "number" type values in JS, what are some of the edge cases, and how to check them.

When writing programs, it is important to know the limits of each type of values.

M-Abdoon · 2025-10-20T14:53:33Z

Thank you for the feedback. Changes have been made.

…est cases and added throw error

M-Abdoon · 2025-10-20T22:53:23Z

Changes have been made.

cjyuan · 2025-10-21T00:20:46Z

Changes look good. Well done.

M-Abdoon added 3 commits October 10, 2025 17:12

count.js and count.test.js completed

1e5cad7

get-ordinal-numbers.js completed

a42937d

repeat.js and repeat.test.js completed

9600443

M-Abdoon added the Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. label Oct 11, 2025

cjyuan added Review in progress This review is currently being reviewed. This label will be replaced by "Reviewed" soon. and removed Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. labels Oct 18, 2025

cjyuan reviewed Oct 18, 2025

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cjyuan added Reviewed Volunteer to add when completing a review with trainee action still to take. and removed Review in progress This review is currently being reviewed. This label will be replaced by "Reviewed" soon. labels Oct 18, 2025

M-Abdoon added 3 commits October 19, 2025 12:07

Updated the funciton so it handels other tests, and added more tests too

c0d9240

function repeat() should return false when negative number passed

f6314c3

updated function repeat() and its tests

ad2180d

M-Abdoon added Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. and removed Reviewed Volunteer to add when completing a review with trainee action still to take. labels Oct 19, 2025

cjyuan reviewed Oct 19, 2025

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cjyuan added Reviewed Volunteer to add when completing a review with trainee action still to take. and removed Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. labels Oct 19, 2025

M-Abdoon added 3 commits October 20, 2025 14:05

is shortened inside the function getOrdinalNumber()

94348cb

is shortened inside the function getOrdinalNumber()

b46e59d

is shortened inside the function getOrdinalNumber()

f55b3a2

M-Abdoon added Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. and removed Reviewed Volunteer to add when completing a review with trainee action still to take. labels Oct 20, 2025

cjyuan added Reviewed Volunteer to add when completing a review with trainee action still to take. and removed Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. labels Oct 20, 2025

M-Abdoon added 4 commits October 20, 2025 23:31

changed condition rule in function getOrdinalNumber() and added new t…

f06c4f9

…est cases and added throw error

test cases recategorising

25b1868

test cases recategorising -- styling

06a987e

corrected condition rule to include NaN and Infinity numbers

4b42131

M-Abdoon added Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. and removed Reviewed Volunteer to add when completing a review with trainee action still to take. labels Oct 20, 2025

cjyuan added Complete Volunteer to add when work is complete and all review comments have been addressed. and removed Needs Review Trainee to add when requesting review. PRs without this label will not be reviewed. labels Oct 21, 2025

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Glasgow | 25-ITP-SEP | Mohammed Abdoon | Sprint 3 | Coursework/2-practice-tdd #746

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M-Abdoon commented Oct 10, 2025

Learners, PR Template

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M-Abdoon commented Oct 19, 2025

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M-Abdoon commented Oct 20, 2025

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