Migrate doctest for MergeSort.js

(also remove inline test driver code)

Author: defaude

Sorts/MergeSort.js

@@ -1,40 +1,21 @@
-/**
- * Merge Sort is an algorithm where the main list is divided down into two half
- * sized lists, which then have merge sort called on these two smaller lists
- * recursively until there is only a sorted list of one.
+/*
+ * MergeSort implementation.
+ *
+ * Merge Sort is an algorithm where the main list is divided down into two half sized lists, which then have merge sort
+ * called on these two smaller lists recursively until there is only a sorted list of one.
  *
  * On the way up the recursive calls, the lists will be merged together inserting
  * the smaller value first, creating a larger sorted list.
  */
 
 /**
- * Sort and merge two given arrays
- * @param {Array} list1 - sublist to break down
- * @param {Array} list2 - sublist to break down
- * @return {Array} merged list
+ * Sort and merge two given arrays.
+ *
+ * @param {Array} list1 Sublist to break down.
+ * @param {Array} list2 Sublist to break down.
+ * @return {Array} The merged list.
  */
-/*
-*  Doctests
-* > merge([5, 4],[ 1, 2, 3])
-*  [1, 2, 3, 5, 4]
-* > merge([],[1, 2])
-*  [1, 2]
-* > merge([1, 2, 3], [1])
-*  [1, 1, 2, 3]
-* > merge([], [])
-*  []
-*
-* > mergeSort([5, 4])
-*  [4, 5]
-* > mergeSort([8, 4, 10, 15, 9])
-*  [4, 8, 9, 10, 15]
-* > mergeSort([1, 2, 3])
-*  [1, 2, 3]
-* > mergeSort([ ])
-*  [ ]
-*/
-
-function merge (list1, list2) {
+export function merge (list1, list2) {
   const results = []
   let i = 0
   let j = 0
@@ -51,11 +32,12 @@ function merge (list1, list2) {
 }
 
 /**
- * Break down the lists into smaller pieces to be merged
- * @param {Array} list - list to be sorted
- * @return {Array} sorted list
+ * Break down the lists into smaller pieces to be merged.
+ *
+ * @param {Array} list List to be sorted.
+ * @return {Array} The sorted list.
  */
-function mergeSort (list) {
+export function mergeSort (list) {
   if (list.length < 2) return list
 
   const listHalf = Math.floor(list.length / 2)
@@ -64,9 +46,3 @@ function mergeSort (list) {
 
   return merge(mergeSort(subList1), mergeSort(subList2))
 }
-
-// Merge Sort Example
-const unsortedArray = [10, 5, 3, 8, 2, 6, 4, 7, 9, 1]
-const sortedArray = mergeSort(unsortedArray)
-
-console.log('Before:', unsortedArray, 'After:', sortedArray)

Sorts/test/MergeSort.test.js

@@ -0,0 +1,23 @@
+import { merge, mergeSort } from '../MergeSort'
+
+describe('merge', () => {
+  it('should merge arrays correctly', () => {
+    expect(merge([5, 4], [1, 2, 3])).toEqual([1, 2, 3, 5, 4])
+    expect(merge([], [1, 2])).toEqual([1, 2])
+    expect(merge([1, 2, 3], [1])).toEqual([1, 1, 2, 3])
+    expect(merge([], [])).toEqual([])
+  })
+})
+
+describe('MergeSort', () => {
+  it('should work for empty arrays', () => {
+    expect(mergeSort([])).toEqual([])
+  })
+
+  it('should sort arrays correctly', () => {
+    expect(mergeSort([5, 4])).toEqual([4, 5])
+    expect(mergeSort([8, 4, 10, 15, 9])).toEqual([4, 8, 9, 10, 15])
+    expect(mergeSort([1, 2, 3])).toEqual([1, 2, 3])
+    expect(mergeSort([10, 5, 3, 8, 2, 6, 4, 7, 9, 1])).toEqual([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
+  })
+})