Add tests for Project Euler Problem 5 + minor refactor (#1691)

Project-Euler/Problem005.js

@@ -5,11 +5,9 @@ Smallest multiple
 What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?
 */
 
-export const findSmallestMultiple = () => {
-  const divisors = [
-    20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2
-  ]
-  let num = 21
+export const findSmallestMultiple = (maxDivisor) => {
+  const divisors = Array.from({ length: maxDivisor }, (_, i) => i + 1)
+  let num = maxDivisor + 1
   let result
 
   while (!result) {

Project-Euler/test/Problem005.test.js

@@ -0,0 +1,12 @@
+import { expect } from 'vitest'
+import { findSmallestMultiple } from '../Problem005.js'
+
+describe.concurrent('Find smallest multiple', () => {
+  test.each([
+    [10, 2520],
+    [15, 360360],
+    [20, 232792560]
+  ])('max divisor -> %i, smallest multiple -> %i', (a, expected) => {
+    expect(findSmallestMultiple(a)).toBe(expected)
+  })
+})