London | 26-ITP-Sep | Diana Ausiejute | Sprint 2 | Practice TDD

practice-tdd/count.js

@@ -1,3 +1,9 @@
 export function countChar(stringOfCharacters, findCharacter) {
-  return 5
+  let count = 0;
+  for (let i = 0; i < stringOfCharacters.length; i++) {
+    if (stringOfCharacters[i] === findCharacter) {
+      count++;
+    }
+  }
+  return count;
 }

practice-tdd/count.test.js

@@ -17,8 +17,29 @@ test("should count multiple occurrences of a character", () => {
   expect(count).toEqual(5);
 });
 
+test("should count multiple occurences of a character in a multiple character string", () => {
+  const str = "banana";
+  const char = "a";
+  const count = countChar(str, char);
+  expect(count).toEqual(3);
+});
+
 // Scenario: No Occurrences
 // Given the input string `str`,
 // 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 count zero occurrences of a character", () => {
+  const str = "aaaa";
+  const char = "b";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});
+
+test("should return 0 for no input", () => {
+  const str = "";
+  const char = "b";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});

practice-tdd/get-ordinal-number.js

@@ -1,3 +1,25 @@
 export function getOrdinalNumber(num) {
-  return "1st";
+  if (num === null || num === undefined || num === "" || num < 0) {
+    throw new Error("Invalid input!");
+  }
+
+  if (typeof num !== "number" || !isFinite(num)) {
+    throw new Error("Invalid input!");
+  }
+
+  const lastDigit = num % 10;
+  const lastTwoDigits = num % 100;
+
+  if (lastTwoDigits >= 11 && 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`;
+  }
+  return `${num}th`;
 }

practice-tdd/get-ordinal-number.test.js

@@ -18,3 +18,35 @@ test("should append 'st' for numbers ending with 1, except those ending with 11"
   expect(getOrdinalNumber(21)).toEqual("21st");
   expect(getOrdinalNumber(131)).toEqual("131st");
 });
+
+test("should append 'nd' for numbers ending with 2, except those ending with 12", () => {
+  expect(getOrdinalNumber(2)).toEqual("2nd");
+  expect(getOrdinalNumber(32)).toEqual("32nd");
+  expect(getOrdinalNumber(102)).toEqual("102nd");
+});
+
+test("should append 'rd' for numbers ending with 3, except those ending with 13", () => {
+  expect(getOrdinalNumber(3)).toEqual("3rd");
+  expect(getOrdinalNumber(53)).toEqual("53rd");
+  expect(getOrdinalNumber(123)).toEqual("123rd");
+});
+
+test("should append 'th for special cases 11, 12, 13", () => {
+  expect(getOrdinalNumber(11)).toEqual("11th");
+  expect(getOrdinalNumber(12)).toEqual("12th");
+  expect(getOrdinalNumber(13)).toEqual("13th");
+});
+
+test("should append 'th' for the rest of the numbers", () => {
+  expect(getOrdinalNumber(9)).toEqual("9th");
+  expect(getOrdinalNumber(20)).toEqual("20th");
+  expect(getOrdinalNumber(108)).toEqual("108th");
+});
+
+test("should throw an error if the input is invalid", () => {
+  expect(() => getOrdinalNumber("")).toThrow("Invalid input!");
+  expect(() => getOrdinalNumber("fifty two")).toThrow("Invalid input!");
+  expect(() => getOrdinalNumber(-3)).toThrow("Invalid input!");
+  expect(() => getOrdinalNumber(null)).toThrow("Invalid input!");
+  expect(() => getOrdinalNumber(undefined)).toThrow("Invalid input!");
+});

practice-tdd/repeat-str.js

@@ -1,5 +1,18 @@
-export function repeatStr() {
-  // Your implementation of this function must *not* call String.prototype.repeat (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat).
-  // The goal is to re-implement that function, not to use it.
-  return "hellohellohello";
+// Your implementation of this function must *not* call String.prototype.repeat (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat).
+// The goal is to re-implement that function, not to use it.#
+export function repeatStr(str, count) {
+  if (Number.isInteger(count) && count < 0) {
+    throw new Error(`Invalid input`);
+  }
+  if (count === 0) {
+    return "";
+  }
+
+  if (Number.isInteger(count) && count > 0) {
+    let result = "";
+    for (let i = 0; i < count; i++) {
+      result += str;
+    }
+    return result;
+  }
 }

practice-tdd/repeat-str.test.js

@@ -21,12 +21,39 @@ test("should repeat the string count times", () => {
 // When the repeatStr function is called with these inputs,
 // Then it should return the original `str` without repetition.
 
+test("should repeat the string 1 time", () => {
+  const str = "hello";
+  const count = 1;
+  const repeatedStr = repeatStr(str, count);
+  expect(repeatedStr).toEqual("hello");
+});
+
 // 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 repeat the string 0 times", () => {
+  const str = "hello";
+  const count = 0;
+  const repeatedStr = repeatStr(str, count);
+  expect(repeatedStr).toEqual("");
+});
+
+test("should repeat the string 0 times", () => {
+  const str = "";
+  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 = "hello";
+  const count = -2;
+  expect(() => repeatStr(str, count)).toThrow("Invalid input");
+});