Implement repeatStr function and add Jest tests

- Implement repeatStr to repeat a string a given number of times
- Handles count = 0, count = 1, count > 1
- Throws error for negative counts
- Add Jest tests covering:
  - multiple repetitions
  - single repetition
  - zero repetitions
  - negative counts

Author: codebyshay

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

@@ -1,5 +1,13 @@
 function countChar(stringOfCharacters, findCharacter) {
-  return 5
+  let count = 0;
+
+  for (let i = 0; i < stringOfCharacters.length; i++) {
+    if (stringOfCharacters[i] === findCharacter) {
+      count++;
+    }
+  }
+
+  return count;
 }
 
 module.exports = countChar;

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

@@ -9,7 +9,6 @@ const countChar = require("./count");
 // And a character `char` that occurs one or more times in `str` (e.g., 'a' in 'aaaaa'),
 // When the function is called with these inputs,
 // Then it should correctly count occurrences of `char`.
-
 test("should count multiple occurrences of a character", () => {
   const str = "aaaaa";
   const char = "a";
@@ -22,3 +21,34 @@ test("should count multiple occurrences of a character", () => {
 // And a character `char` that does not exist within `str`.
 // When the function is called with these inputs,
 // Then it should return 0, indicating that no occurrences of `char` were found.
+test("should return 0 when character does not occur in string", () => {
+  const str = "hello";
+  const char = "z";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});
+
+// Scenario: Empty String
+// Given an empty string `str`,
+// And any character `char`,
+// When the function is called with these inputs,
+// Then it should return 0, because no characters exist in the string.
+test("should return 0 when string is empty", () => {
+  const str = "";
+  const char = "a";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});
+
+// Scenario: Single Occurrence
+// Given the input string `str`,
+// And a character `char` that occurs exactly once within `str`.
+// When the function is called with these inputs,
+// Then it should return 1, indicating a single occurrence of `char`.
+test("should return 1 when character occurs once", () => {
+  const str = "hello";
+  const char = "h";
+  const count = countChar(str, char);
+  expect(count).toEqual(1);
+});
+

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

@@ -1,5 +1,11 @@
-function getOrdinalNumber(num) {
-  return "1st";
+function getOrdinalNumber(n) {
+  const j = n % 10,
+        k = n % 100;
+  if (k >= 11 && k <= 13) return n + "th";
+  if (j === 1) return n + "st";
+  if (j === 2) return n + "nd";
+  if (j === 3) return n + "rd";
+  return n + "th";
 }
 
 module.exports = getOrdinalNumber;

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

@@ -18,3 +18,26 @@ test("should append 'st' for numbers ending with 1, except those ending with 11"
   expect(getOrdinalNumber(21)).toEqual("21st");
   expect(getOrdinalNumber(131)).toEqual("131st");
 });
+
+// Ends with 2, except 12
+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");
+});
+
+// Ends with 3, except 13
+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");
+});
+
+// All others
+test("should append 'th' for all other numbers", () => {
+  expect(getOrdinalNumber(4)).toEqual("4th");
+  expect(getOrdinalNumber(11)).toEqual("11th");
+  expect(getOrdinalNumber(12)).toEqual("12th");
+  expect(getOrdinalNumber(13)).toEqual("13th");
+  expect(getOrdinalNumber(14)).toEqual("14th");
+});

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

@@ -1,5 +1,6 @@
-function repeatStr() {
-  return "hellohellohello";
+function repeatStr(str, count) {
+  if (count < 0) throw new Error("Count must be a non-negative integer");
+  return str.repeat(count);
 }
 
 module.exports = repeatStr;

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

@@ -20,13 +20,34 @@ test("should repeat the string count times", () => {
 // Given a target string `str` and a `count` equal to 1,
 // When the repeatStr function is called with these inputs,
 // Then it should return the original `str` without repetition.
+test("should return the string itself when count is 1", () => {
+  const str = "world";
+  const count = 1;
+  const repeatedStr = repeatStr(str, count);
+  expect(repeatedStr).toEqual("world");
+});
+
 
 // Case: Handle count of 0:
 // Given a target string `str` and a `count` equal to 0,
 // When the repeatStr function is called with these inputs,
 // Then it should return an empty string.
+test("should return an empty string when count is 0", () => {
+  const str = "hello";
+  const count = 0;
+  const repeatedStr = repeatStr(str, count);
+  expect(repeatedStr).toEqual("");
+});
 
 // Case: Handle negative count:
 // Given a target string `str` and a negative integer `count`,
 // When the repeatStr function is called with these inputs,
 // Then it should throw an error, as negative counts are not valid.
+test("should throw an error for negative count", () => {
+  const str = "oops";
+  const count = -3;
+
+  expect(() => {
+    repeatStr(str, count);
+  }).toThrow("Count must be a non-negative integer");
+});