<?php declare(strict_types=1); use function App\flattenArray; it('flattens an array', function ( array $input, array $expected ): void { $result = flattenArray($input); assertSame($expected, $result); })->with([ [ 'input' => [1, 2, 3], 'expected' => [1, 2, 3], ], [ 'input' => [1, [2, 3, null, 4], [null], 5], 'expected' => [1, 2, 3, 4, 5], ], [ 'input' => [1, [2, [[3]], [4, [[5]]], 6, 7], 8], 'expected' => [1, 2, 3, 4, 5, 6, 7, 8], ], [ 'input' => [null, [[[null]]], null, null, [[null, null], null], null], 'expected' => [], ] ]);