London | 26-ITP-Sept | Mars Adesina | Sprint 2 | Practice TDD

practice-tdd/count.js

@@ -1,3 +1,10 @@
 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

@@ -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 occur", () => {
+  const str = "aaaabcd";
+  const char = "e";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});

practice-tdd/get-ordinal-number.js

@@ -1,3 +1,17 @@
 export function getOrdinalNumber(num) {
-  return "1st";
+  if (num % 100 === 11) {
+    return `${num}th`;
+  } else if (num % 10 === 1) {
+    return `${num}st`;
+  } else if (num % 100 === 12) {
+    return `${num}th`;
+  } else if (num % 10 === 2) {
+    return `${num}nd`;
+  } else if (num % 100 === 13) {
+    return `${num}th`;
+  } else if (num % 10 === 3) {
+    return `${num}rd`;
+  } else {
+    return `${num}th`;
+  }
 }

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

@@ -18,3 +18,28 @@ 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 "th" to numbers ending in 11, 12, or 13', () => {
+  expect(getOrdinalNumber(11)).toEqual("11th");
+  expect(getOrdinalNumber(12)).toEqual("12th");
+  expect(getOrdinalNumber(13)).toEqual("13th");
+});
+
+test('should append "nd" to numbers ending in 2, apart from those ending in 12', () => {
+  expect(getOrdinalNumber(2)).toEqual("2nd");
+  expect(getOrdinalNumber(32)).toEqual("32nd");
+  expect(getOrdinalNumber(142)).toEqual("142nd");
+});
+
+test('should append "rd" to numbers ending in 3, apart from those ending in 13', () => {
+  expect(getOrdinalNumber(3)).toEqual("3rd");
+  expect(getOrdinalNumber(33)).toEqual("33rd");
+  expect(getOrdinalNumber(143)).toEqual("143rd");
+});
+
+test(`should append "th" to other numbers that don't end in 1, 2, or 3`, () => {
+  expect(getOrdinalNumber(4)).toEqual("4th");
+  expect(getOrdinalNumber(10)).toEqual("10th");
+  expect(getOrdinalNumber(24)).toEqual("24th");
+  expect(getOrdinalNumber(100)).toEqual("100th");
+});

practice-tdd/repeat-str.js

@@ -1,5 +1,10 @@
-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";
+export function repeatStr(str, count) {
+  if (count < 0) {
+    throw new Error("warning! Count cannot be negative!");
+  }
+  let result = "";
+  for (let i = 0; i < count; i++) {
+    result += str;
+  }
+  return result;
 }

practice-tdd/repeat-str.test.js

@@ -20,13 +20,30 @@ 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 original string when count equals 1", () => {
+  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 return an empty string when count equals 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 when count is a negative number", () => {
+  const str = "hello";
+  const count = -2;
+  expect(() => repeatStr(str, count)).toThrow();
+});