Coursework 2-practice-tdd

Author: mohsenzamanist

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

@@ -1,5 +1,7 @@
 function countChar(stringOfCharacters, findCharacter) {
-  return 5
+  return stringOfCharacters
+    .split("")
+    .reduce((acc, curr) => acc + (curr === findCharacter ? 1 : 0), 0);
 }
 
 module.exports = countChar;

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

@@ -1,14 +1,14 @@
 // 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,
+// 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 may occur multiple times with overlaps within str (e.g., 'a' in 'aaaaa'),
+// 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 overlapping occurrences of char (e.g., 'a' appears five times in 'aaaaa').
+// Then it should correctly count occurrences of `char`.
 
 test("should count multiple occurrences of a character", () => {
   const str = "aaaaa";
@@ -18,7 +18,14 @@ test("should count multiple occurrences of a character", () => {
 });
 
 // Scenario: No Occurrences
-// Given the input string str,
-// And a character char that does not exist within the case-sensitive str,
+// 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 the char were found in the case-sensitive str.
+
+// Then it should return 0, indicating that no occurrences of `char` were found.
+test("should return 0, since there are no occurrences of a character", () => {
+  const char = "a";
+  const str = "AABBFFSAA";
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});

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

@@ -1,5 +1,22 @@
 function getOrdinalNumber(num) {
-  return "1st";
+  if ([11, 12, 13].includes(num)) return `${num}th`;
+  const lastDigit = String(num).slice(-1);
+  const restOfNum = String(num).slice(0, -1);
+  let ordinalResult = "";
+  switch (lastDigit) {
+    case "1":
+      ordinalResult = restOfNum + "1st";
+      break;
+    case "2":
+      ordinalResult = restOfNum + "2nd";
+      break;
+    case "3":
+      ordinalResult = restOfNum + "3rd";
+      break;
+    default:
+      ordinalResult = restOfNum + lastDigit + "th";
+  }
+  return ordinalResult;
 }
 
 module.exports = getOrdinalNumber;

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

@@ -1,13 +1,46 @@
 const getOrdinalNumber = require("./get-ordinal-number");
-// In this week's prep, we started implementing getOrdinalNumber
+// 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
+// Continue testing and implementing getOrdinalNumber for additional cases.
+// Write your tests using Jest — remember to run your tests often for continual feedback.
 
-// Case 1: Identify the ordinal number for 1
-// When the number is 1,
-// Then the function should return "1st"
+// 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.
 
-test("should return '1st' for 1", () => {
+// 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(31)).toEqual("131st");
+});
+
+test("should return '2nd' for 2", () => {
+  expect(getOrdinalNumber(2)).toEqual("2nd");
+});
+
+test("should return '3rd' for 3", () => {
+  expect(getOrdinalNumber(3)).toEqual("3rd");
+});
+test("should return '4th' for 4", () => {
+  expect(getOrdinalNumber(4)).toEqual("4th");
+});
+test("should return '5th' for 5", () => {
+  expect(getOrdinalNumber(5)).toEqual("5th");
+});
+test("should return '11th' for 11", () => {
+  expect(getOrdinalNumber(11)).toEqual("11th");
+});
+test("should return '21st' for 21", () => {
+  expect(getOrdinalNumber(21)).toEqual("21st");
+});
+test("should return '32nd' for 32", () => {
+  expect(getOrdinalNumber(32)).toEqual("32nd");
+});
+test("should return '53rd' for 53", () => {
+  expect(getOrdinalNumber(53)).toEqual("53rd");
 });

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

@@ -1,5 +1,6 @@
-function repeatStr() {
-  return "hellohellohello";
+function repeatStr(str, count) {
+  if (count < 0) throw new Error("Can not repeat negative times.");
+  return str.repeat(count);
 }
 
 module.exports = repeatStr;

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

@@ -1,13 +1,13 @@
 // Implement a function repeatStr
 const repeatStr = require("./repeat-str");
-// Given a target string str and a positive integer count,
+// Given a target string `str` and a positive integer `count`,
 // When the repeatStr function is called with these inputs,
 // Then it should:
 
-// case: repeat String:
-// Given a target string str and a positive integer count,
+// 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 repeat the str count times and return a new string containing the repeated str values.
+// 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 +16,33 @@ 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,
+// 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, ensuring that a count of 1 results in no repetition.
+test("should repeat the string count times", () => {
+  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,
+// 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, ensuring that a count of 0 results in an empty output.
+// Then it should return an empty string.
+test("should repeat the string count times", () => {
+  const str = "hello";
+  const count = 0;
+  const repeatedStr = repeatStr(str, count);
+  expect(repeatedStr).toEqual("");
+});
 
-// case: Negative Count:
-// Given a target string str and a negative integer count,
+// 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 or return an appropriate error message, as negative counts are not valid.
+// Then it should throw an error, as negative counts are not valid.
+test("should repeat the string count times", () => {
+  const str = "hello";
+  const count = -3;
+  expect(() => repeatStr(str, count)).toThrow("Can not repeat negative times.");
+});