Added test coverage

Author: aran112000

tests/SanitizeArraysTest.php

@@ -0,0 +1,11 @@
+<?php
+
+use Crwlr\QueryString\Query;
+
+test('Duplicate query string keys are correctly converted to arrays', function () {
+    expect(Query::fromString('test=1&test2=2&test=2&test[]=3')->toArray())
+        ->toEqual([
+            'test' => [1, 2, 3],
+            'test2' => 2,
+        ]);
+});