Birmingham | 26-ITP-May | Gabriel Pawuoi | Sprint 1 | implement sum function and tests

Sprint-1/implement/sum.js

@@ -1,4 +1,5 @@
 function sum(elements) {
+  return elements.filter(n => typeof n === "number").reduce((acc, n) => acc + n, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,26 @@ 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([])).toEqual(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([42])).toEqual(42);
+});
 
-// 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", () => {
+  expect(sum([10, -5, 3])).toEqual(8);
+});
 
-// 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 numbers, returns the correct total", () => {
+  expect(sum([1.5, 2.5])).toEqual(4);
+});
 
-// 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 them and sums the rest", () => {
+  expect(sum(["hey", 10, "hi", 60, 10])).toEqual(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 0", () => {
+  expect(sum(["a", "b"])).toEqual(0);
+});