merge: Add test case and fix pigeonHoleSort Algorithm (#967)

Sorts/PigeonHoleSort.js

@@ -29,4 +29,5 @@ export function pigeonHoleSort (arr) {
       arr[index++] = j + min
     }
   }
+  return arr
 }

Sorts/test/pigeonHoleSort.test.js

@@ -0,0 +1,19 @@
+import { pigeonHoleSort } from '../PigeonHoleSort'
+
+test('The pigeonHoleSort of the array [1, 4, 3, 2] is [1, 2, 3, 4]', () => {
+  const arr = [1, 4, 3, 2]
+  const res = pigeonHoleSort(arr)
+  expect(res).toEqual([1, 2, 3, 4])
+})
+
+test('The pigeonHoleSort of the array [5, 4, 1, 2] is [1, 2, 4, 5]', () => {
+  const arr = [5, 4, 1, 2]
+  const res = pigeonHoleSort(arr)
+  expect(res).toEqual([1, 2, 4, 5])
+})
+
+test('The pigeonHoleSort of the array [18, 31, 29, 35, 11] is [11, 18, 29, 31, 35]', () => {
+  const arr = [18, 31, 29, 35, 11]
+  const res = pigeonHoleSort(arr)
+  expect(res).toEqual([11, 18, 29, 31, 35])
+})