payloadCart example

    }

    public static function cleanupCustomFieldsProvider(): \Generator
    {
        yield 'Test empty cart' => [
            new Cart('test'),
            [],
        ];

        yield 'Test strip payload' => [
            self::payloadCart('foo', ['customFields' => ['bar' => 1]]),
            ['foo' => ['customFields' => []], 'foo-child' => ['customFields' => []]],
        ];

        yield 'Test allowed field' => [
            self::payloadCart('foo', ['customFields' => ['bar' => 1]]),
            ['foo' => ['customFields' => ['bar' => 1]], 'foo-child' => ['customFields' => ['bar' => 1]]],
            ['bar'],
        ];

        yield 'Test multiple allowed fields' => [
            self::payloadCart('foo', ['customFields' => ['bar' => 1, 'baz' => 2]]),
            [