wrote implemention for sum function to add integers and wrote multiple test cases for it to meet acceptance criteria

Author: fayaz551

Sprint-1/implement/sum.js

@@ -1,4 +1,22 @@
 function sum(elements) {
+  if (!Array.isArray(elements)) {
+    return 0;
+  }
+
+  // Filter only numeric values
+  const numbers = elements.filter(function (item) {
+    return typeof item === "number" && !isNaN(item);
+  });
+
+  // If no numeric values, return 0
+  if (numbers.length === 0) {
+    return 0;
+  }
+
+  // Add the numbers
+  return numbers.reduce(function (total, value) {
+    return total + value;
+  }, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,41 @@ const sum = require("./sum.js");
 // Given an empty array
 // When passed to the sum function
 // Then it should return 0
-test.todo("given an empty array, returns 0")
+test("given an empty array, returns 0", () => {
+  expect(sum([])).toBe(0);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
+test("given an array with just one number, returns that number", () => {
+  expect(sum([5])).toBe(5);
+});
 
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
+test("given an array containing negative numbers, returns the correct total sum", () => {
+  expect(sum([-10, 20, -5])).toBe(5);
+});
 
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
+test("given an array with decimal/float numbers, returns the correct total sum", () => {
+  expect(sum([3.14, 2.71, 1.41])).toBe(7.26);
+});
 
 // Given an array containing non-number values
 // When passed to the sum function
 // Then it should ignore the non-numerical values and return the sum of the numerical elements
+test("given an array containing non-number values, ignores non-numerical values and returns the sum of numerical elements", () => {
+  expect(sum(['hey', 10, 'hi', 60, 10])).toBe(80);
+});
 
 // Given an array with only non-number values
 // When passed to the sum function
 // Then it should return the least surprising value given how it behaves for all other inputs
+test("given an array with only non-number values, returns the least surprising value", () => {
+  expect(sum(['hey', 'hi', 'hello'])).toBe(0);
+});