London | 26-ITP-May | Dipa Sarker | Sprint 3 | Practice TDD

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

@@ -1,5 +1,12 @@
-function countChar(stringOfCharacters, findCharacter) {
-  return 5
+function countChar(str, char) {
+  let count = 0;
+  for (let i = 0; i < str.length; i++) {
+    if (str[i] === char) {
+      count++;
+    }
+  }
+  return count;
 }
 
+
 module.exports = countChar;

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

@@ -1,24 +1,70 @@
-// 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: 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 no occurrences of a character", () => {
+  const str = "aaaaa";
+  const char = "b";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});
+
+test("should count no occurrences of a character", () => {
+  const str = "";
+  const char = "a";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});
+
+test("should count minnimum occurrence of a character", () => {
+  const str = "a";
+  const char = "a";
+  const count = countChar(str, char);
+  expect(count).toEqual(1);
+});
+
+test("should count no occurrences of a character", () => {
+  const str = "b";
+  const char = "a";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});
+
+test("should count occurrence of special character", () => {
+  const str = "!!!!";
+  const char = "!";
+  const count = countChar(str, char);
+  expect(count).toEqual(4);
+});
+
+test("should count character at the beggining", () => {
+  const str = "cow";
+  const char = "c";
+  const count = countChar(str, char);
+  expect(count).toEqual(1);
+});
+
+test("should count character at the end", () => {
+  const str = "apple";
+  const char = "e";
+  const count = countChar(str, char);
+  expect(count).toEqual(1);
+});
+
+test("should count lowercase character", () => {
+  const str = "Apple";
+  const char = "a";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});
+
+test("should count occurrence of spaces", () => {
+  const str = "a b c";
+  const char = " ";
+  const count = countChar(str, char);
+  expect(count).toEqual(2);
+});

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

@@ -1,5 +1,15 @@
 function getOrdinalNumber(num) {
-  return "1st";
+  const lastDigit = num % 10;
+  const lastTwoDigits = num % 100;
+  if (lastDigit === 1 && lastTwoDigits !== 11) {
+    return `${num}st`;
+  } else if (lastDigit === 2 && lastTwoDigits !== 12) {
+    return `${num}nd`;
+  } else if (lastDigit === 3 && lastTwoDigits !== 13) {
+    return `${num}rd`;
+  } else {
+    return `${num}th`;
+  }
 }
 
 module.exports = getOrdinalNumber;

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

@@ -1,20 +1,40 @@
 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.
-
-// 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 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");
+describe("Numbers ending with 1", () => {
+  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");
+  });
+});
+describe("Numbers ending with 2", () => {
+  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(432)).toEqual("432nd");
+  });
+});
+describe("Numbers ending with 3", () => {
+  test("should append 'rd' for numbers ending with 3, except those ending with 13", () => {
+    expect(getOrdinalNumber(3)).toEqual("3rd");
+    expect(getOrdinalNumber(33)).toEqual("33rd");
+    expect(getOrdinalNumber(203)).toEqual("203rd");
+  });
+});
+describe("Numbers ending with th", () => {
+  test("should append 'th' for numbers ending with 4-0, except those ending with 11, 12, 13", () => {
+    expect(getOrdinalNumber(4)).toEqual("4th");
+    expect(getOrdinalNumber(66)).toEqual("66th");
+    expect(getOrdinalNumber(100)).toEqual("100th");
+  });
+});
+describe("Numbers ending with th", () => {
+  test("should append 'th' for numbers ending with 11, 12, 13", () => {
+    expect(getOrdinalNumber(11)).toEqual("11th");
+    expect(getOrdinalNumber(12)).toEqual("12th");
+    expect(getOrdinalNumber(13)).toEqual("13th");
+    expect(getOrdinalNumber(111)).toEqual("111th");
+    expect(getOrdinalNumber(212)).toEqual("212th");
+    expect(getOrdinalNumber(313)).toEqual("313th");
+  });
 });

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

@@ -1,7 +1,12 @@
-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";
+function repeatStr(str, count) {
+  if (count < 0) {
+    throw Error("Negative counts are invalid");
+  }
+  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

@@ -1,13 +1,4 @@
-// Implement a function repeatStr
 const repeatStr = require("./repeat-str");
-// Given a target string `str` and a positive integer `count`,
-// When the repeatStr function is called with these inputs,
-// Then it should:
-
-// Case: handle multiple repetitions:
-// Given a target string `str` and a positive integer `count` greater than 1,
-// When the repeatStr function is called with these inputs,
-// Then it should return a string that contains the original `str` repeated `count` times.
 
 test("should repeat the string count times", () => {
   const str = "hello";
@@ -16,17 +7,25 @@ test("should repeat the string count times", () => {
   expect(repeatedStr).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 without repetition", () => {
+  const str = "hello";
+  const count = 1;
+  const repeatedStr = repeatStr(str, count);
+  expect(repeatedStr).toEqual("hello");
+});
+
+test("should return empty string", () => {
+  const str = "hello";
+  const count = 0;
+  const repeatedStr = repeatStr(str, count);
+  expect(repeatedStr).toEqual("");
+});
 
-// 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 throw an error for negative counts", () => {
+  const str = "hello";
+  const count = -1;
 
-// 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.
+  expect(() => {
+    repeatStr(str, count);
+  }).toThrow("Negative counts are invalid");
+});