phpstream\tests\unit\operations\FilterOperationTest::testFiltering PHP Method

    public function testFiltering()
    {
        $filter = new FilterOperation([1, 2, 3, 4, 5], function ($value) {
            return $value % 2 == 0;
        });
        $result = iterator_to_array($filter);
        $this->assertEquals([1 => 2, 3 => 4], $result);
    }