London | 26-ITP-Jan | Xuanming Hu | Sprint 3 | Practice TDD

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

@@ -22,3 +22,9 @@ 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 exist in the string", () => {
+  const str = "hello world";
+  const char = "x";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});

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

@@ -1,5 +1,20 @@
 function getOrdinalNumber(num) {
-  return "1st";
+  const lastDigit = num % 10;
+  const lastTwoDigits = num % 100;
+
+  if (lastTwoDigits === 11 || lastTwoDigits === 12 || lastTwoDigits === 13) {
+    return num + "th";
+  }
+
+  if (lastDigit === 1) {
+    return num + "st";
+  } else if (lastDigit === 2) {
+    return num + "nd";
+  } else if (lastDigit === 3) {
+    return num + "rd";
+  } else {
+    return num + "th";
+  }
 }
 
 module.exports = getOrdinalNumber;

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

@@ -13,8 +13,36 @@ const getOrdinalNumber = require("./get-ordinal-number");
 // Case 1: Numbers ending with 1 (but not 11)
 // When the number ends with 1, except those ending with 11,
 // Then the function should return a string by appending "st" to the number.
-test("should append 'st' for numbers ending with 1, except those ending with 11", () => {
+test("should append 'st' for numbers ending with 1, except 11", () => {
   expect(getOrdinalNumber(1)).toEqual("1st");
   expect(getOrdinalNumber(21)).toEqual("21st");
-  expect(getOrdinalNumber(131)).toEqual("131st");
+  expect(getOrdinalNumber(31)).toEqual("31st");
+  expect(getOrdinalNumber(101)).toEqual("101st");
+});
+
+test("should append 'nd' for numbers ending with 2, except 12", () => {
+  expect(getOrdinalNumber(2)).toEqual("2nd");
+  expect(getOrdinalNumber(22)).toEqual("22nd");
+  expect(getOrdinalNumber(82)).toEqual("82nd");
+});
+
+test("should append 'rd' for numbers ending with 3, except 13", () => {
+  expect(getOrdinalNumber(3)).toEqual("3rd");
+  expect(getOrdinalNumber(33)).toEqual("33rd");
+  expect(getOrdinalNumber(93)).toEqual("93rd");
+});
+
+test("should append 'th' for the exceptions 11, 12, and 13", () => {
+  expect(getOrdinalNumber(11)).toEqual("11th");
+  expect(getOrdinalNumber(12)).toEqual("12th");
+  expect(getOrdinalNumber(13)).toEqual("13th");
+  expect(getOrdinalNumber(111)).toEqual("111th");
+});
+
+test("should append 'th' for all other numbers", () => {
+  expect(getOrdinalNumber(4)).toEqual("4th");
+  expect(getOrdinalNumber(10)).toEqual("10th");
+  expect(getOrdinalNumber(35)).toEqual("35th");
+  expect(getOrdinalNumber(99)).toEqual("99th");
+  expect(getOrdinalNumber(100)).toEqual("100th");
 });

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

@@ -1,5 +1,14 @@
-function repeatStr() {
-  return "hellohellohello";
+function repeatStr(str, count) {
+  if (typeof count !== "number" || count < 0) {
+    throw new Error("Count must be a non-negative integer");
+  }
+
+  let result = "";
+  for (let i = 0; i < count; i++) {
+    result += str;
+  }
+
+  return result;
 }
 
 module.exports = repeatStr;

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

@@ -10,23 +10,40 @@ const repeatStr = require("./repeat-str");
 // Then it should return a string that contains the original `str` repeated `count` times.
 
 test("should repeat the string count times", () => {
-  const str = "hello";
-  const count = 3;
-  const repeatedStr = repeatStr(str, count);
-  expect(repeatedStr).toEqual("hellohellohello");
+  expect(repeatStr("hello", 3)).toEqual("hellohellohello");
 });
 
 // Case: handle count of 1:
 // 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 original string when count is 1", () => {
+  expect(repeatStr("world", 1)).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", () => {
+  expect(repeatStr("test", 0)).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 when count is negative", () => {
+  expect(() => {
+    repeatStr("error", -2);
+  }).toThrow("Count must be a non-negative integer");
+});
+
+test("should throw an error when count is not a number", () => {
+  expect(() => {
+    repeatStr("error", "-2");
+  }).toThrow("Count must be a non-negative integer");
+});