Added tests for empty collections

Author: andrey-helldar

tests/Unit/SizeSorter/Items/EmptyListTest.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+use DragonCode\SizeSorter\SizeSorter;
+use Illuminate\Support\Collection;
+
+test('array', function () {
+    $actual = SizeSorter::items([])->sort()->all();
+
+    expect($actual)->toBeEmpty()->toBe([]);
+});
+
+test('collection', function () {
+    $actual = SizeSorter::items(new Collection())->sort()->all();
+
+    expect($actual)->toBeEmpty()->toBe([]);
+});