diff --git a/helpers/array.test.js b/helpers/array.test.js
new file mode 100644
index 0000000..a42b5d4
--- /dev/null
+++ b/helpers/array.test.js
@@ -0,0 +1,13 @@
+import { getNextSmaller, getNextBigger } from './array'
+
+test('getPreviousInOrder', () => {
+  const result = getNextSmaller([3, 1, 2, 0, 8, 9, 10], 5)
+
+  expect(result).toEqual(3)
+})
+
+test('getNextInOrder', () => {
+  const result = getNextBigger([7, 8, 9, 3, 1, 2], 4)
+
+  expect(result).toEqual(7)
+})