Cape Town | 2026-ITP-Jan | Isaac Abodunrin | Sprint 3 | Practice TDD

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

@@ -1,5 +1,30 @@
 function countChar(stringOfCharacters, findCharacter) {
-  return 5
+  if (
+    typeof stringOfCharacters != "string" ||
+    typeof findCharacter != "string"
+  ) {
+    throw new Error("Please enter a valid string");
+  }
+
+  if (findCharacter.length != 1) {
+    throw new Error(
+      "Please enter a single character for findCharacter, e.g. 't"
+    );
+  }
+
+  if (stringOfCharacters.length === 0) {
+    throw new Error(
+      "Please enter a non-empty string, e.g. 'A series of unfortunate events'"
+    );
+  }
+
+  let charCount = 0;
+  let lowerCaseChar = findCharacter.toLowerCase();
+  for (char of stringOfCharacters.toLowerCase()) {
+    if (lowerCaseChar === char) charCount++;
+  }
+
+  return charCount;
 }
 
 module.exports = countChar;

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

@@ -1,24 +1,64 @@
-// implement a function countChar that counts the number of times a character occurs in a string
 const countChar = require("./count");
-// Given a string `str` and a single character `char` to search for,
-// When the countChar function is called with these inputs,
-// Then it should:
-
-// Scenario: Multiple Occurrences
-// Given the input string `str`,
-// 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";
-  const count = countChar(str, char);
-  expect(count).toEqual(5);
+
+// Scenario 1: Multiple Occurrences
+test("Should count multiple occurrences of a character", () => {
+  const multipleOccurrences = [
+    { a: "aaaaa", b: "a", c: 5 },
+    { a: "sea saw", b: "s", c: 2 },
+    { a: "Arrested Development", b: "d", c: 2 },
+    { a: "* Star * TV *", b: "*", c: 3 },
+  ];
+
+  for (const { a, b, c } of multipleOccurrences) {
+    expect(countChar(a, b)).toEqual(c);
+  }
+});
+
+// Scenario 2: Single Occurrence
+test("Should count single occurrence of a character", () => {
+  const singleOccurrences = [
+    { a: "a", b: "a" },
+    { a: "Star Light", b: "i" },
+    { a: "!@#$%^&*()", b: "#" },
+    { a: "Why fly?", b: " " },
+  ];
+
+  for (const { a, b } of singleOccurrences) {
+    expect(countChar(a, b)).toEqual(1);
+  }
 });
 
-// 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.
+// Scenario 3: No Occurrence
+test("Should return 0 for no occurrence of a character", () => {
+  const noOccurrences = [
+    { a: "The Rookie", b: "S" },
+    { a: "Angela Bassett", b: "r" },
+    { a: "Santa Clarita Diet", b: "*" },
+    { a: "Better Off Ted", b: "9" },
+  ];
+
+  for (const { a, b } of noOccurrences) {
+    expect(countChar(a, b)).toEqual(0);
+  }
+});
+
+// Scenario 4: Invalid Entries
+test("Should throw an error when given an invalid input", () => {
+  const invalidEntries = [
+    { a: "Courage, the Cowardly Dog", b: "dog" },
+    { a: "Sheep in the Big City", b: 1 },
+    { a: -205, b: "a" },
+    { a: -205, b: 55.5 },
+    { a: true, b: "f" },
+    { a: undefined, b: "f" },
+    { a: null, b: true },
+    { a: false, b: true },
+    { a: [false], b: {} },
+  ];
+
+  for (const { a, b } of invalidEntries) {
+    expect(() => {
+      countChar(a, b);
+    }).toThrow();
+  }
+});

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

@@ -1,5 +1,27 @@
 function getOrdinalNumber(num) {
-  return "1st";
+  if (typeof num != "number" || !Number.isInteger(num)) {
+    throw new Error("Please enter an integer");
+  }
+
+  const positiveNumber = Math.abs(num);
+
+  let suffix;
+
+  switch (true) {
+    case positiveNumber % 10 === 1 && positiveNumber % 100 !== 11:
+      suffix = "st";
+      break;
+    case positiveNumber % 10 === 2 && positiveNumber % 100 !== 12:
+      suffix = "nd";
+      break;
+    case positiveNumber % 10 === 3 && positiveNumber % 100 !== 13:
+      suffix = "rd";
+      break;
+    default:
+      suffix = "th";
+  }
+
+  return `${num}${suffix}`;
 }
 
 module.exports = getOrdinalNumber;

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

@@ -1,20 +1,123 @@
 const getOrdinalNumber = require("./get-ordinal-number");
-// In this week's prep, we started implementing getOrdinalNumber.
 
-// Continue testing and implementing getOrdinalNumber for additional cases.
-// Write your tests using Jest — remember to run your tests often for continual feedback.
+// Case 1: Numbers ending with 1 (but not in 11)
+test("should append 'st' for numbers ending with 1, except those ending with 11", () => {
+  const numbers = [1, 21, 131];
+
+  for (const number of numbers) {
+    expect(getOrdinalNumber(number)).toEqual(`${number}st`);
+  }
+});
 
-// To ensure thorough testing, we need broad scenarios that cover all possible cases.
-// Listing individual values, however, can quickly lead to an unmanageable number of test cases.
-// Instead of writing tests for individual numbers, consider grouping all possible input values
-// into meaningful categories. Then, select representative samples from each category to test.
-// This approach improves coverage and makes our tests easier to maintain.
+// Case 2: Numbers ending with 11
+test("should append 'th' for numbers ending with 11", () => {
+  const numbers = [11, 111, 700011];
 
-// 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", () => {
-  expect(getOrdinalNumber(1)).toEqual("1st");
-  expect(getOrdinalNumber(21)).toEqual("21st");
-  expect(getOrdinalNumber(131)).toEqual("131st");
+  for (const number of numbers) {
+    expect(getOrdinalNumber(number)).toEqual(`${number}th`);
+  }
+});
+
+// Case 3: Numbers ending with 2 (but not in 12)
+test("should append 'nd' for numbers ending in 2", () => {
+  const numbers = [2, 22, 32, 502];
+
+  for (const number of numbers) {
+    expect(getOrdinalNumber(number)).toEqual(`${number}nd`);
+  }
+});
+
+// Case 4: Numbers ending with 12
+test("should append 'th' for numbers ending in 12", () => {
+  const numbers = [12, 212, 312, 5012];
+
+  for (const number of numbers) {
+    expect(getOrdinalNumber(number)).toEqual(`${number}th`);
+  }
+});
+
+// Case 5: Numbers ending in 3 (but not in 13)
+test("should append 'rd' for numbers ending in 3 (but not 13)", () => {
+  const numbers = [3, 23, 33, 1063];
+
+  for (const number of numbers) {
+    expect(getOrdinalNumber(number)).toEqual(`${number}rd`);
+  }
+});
+
+// Case 6: Numbers ending in 13
+test("should append 'th' for numbers ending in 13", () => {
+  const numbers = [13, 113, 613, 713];
+
+  for (const number of numbers) {
+    expect(getOrdinalNumber(number)).toEqual(`${number}th`);
+  }
+});
+
+// Case 7: Numbers ending in 4-10
+test("should append 'th' for numbers ending in 4-10", () => {
+  const lastDigits = [4, 5, 6, 7, 8, 9, 10];
+  const bases = [0, 10, 50, 90, 100];
+
+  for (const lastDigit of lastDigits) {
+    for (const base of bases) {
+      const finalNumber = base + lastDigit;
+      expect(getOrdinalNumber(finalNumber)).toEqual(`${finalNumber}th`);
+    }
+  }
+});
+
+// Case 8: Negative numbers
+test("should return ordinal number for negative integer input", () => {
+  const ordinals = [
+    { a: -2, b: "-2nd" },
+    { a: -1, b: "-1st" },
+    { a: -3, b: "-3rd" },
+    { a: -4, b: "-4th" },
+    { a: -11, b: "-11th" },
+    { a: -12, b: "-12th" },
+    { a: -13, b: "-13th" },
+  ];
+
+  for (const { a, b } of ordinals) {
+    expect(getOrdinalNumber(a)).toEqual(b);
+  }
+});
+
+// Case 9: Decimal representations of integers
+test("should return ordinal number for integer in decimal form", () => {
+  const ordinals = [
+    { a: 1.0, b: "1st" },
+    { a: 2.0, b: "2nd" },
+    { a: 3.0, b: "3rd" },
+    { a: 4.0, b: "4th" },
+    { a: -11.0, b: "-11th" },
+    { a: -12.0, b: "-12th" },
+    { a: -13.0, b: "-13th" },
+  ];
+
+  for (const { a, b } of ordinals) {
+    expect(getOrdinalNumber(a)).toEqual(b);
+  }
+});
+
+// Case 10: Invalid entries
+test("should throw error for invalid inputs", () => {
+  const invalidEntries = [
+    "one",
+    "",
+    [1],
+    null,
+    undefined,
+    9.5,
+    8.00001,
+    {},
+    true,
+  ];
+
+  for (const entry of invalidEntries) {
+    expect(() => {
+      getOrdinalNumber(entry);
+    }).toThrow();
+  }
 });

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

@@ -1,5 +1,13 @@
-function repeatStr() {
-  return "hellohellohello";
+function repeatStr(str, count) {
+  if (typeof str !== "string")
+    throw new Error("Please use a string i.e. 'Hello World'");
+
+  if (!Number.isInteger(count))
+    throw new Error("Please set count to an integer");
+
+  if (count < 0) throw new Error("Please use a count of 0 or greater");
+
+  return str.repeat(count);
 }
 
 module.exports = repeatStr;