<?php
/**
 * Copyright © 2016 Magento. All rights reserved.
 * See COPYING.txt for license details.
 */

/* Create attribute */
/** @var $installer \Magento\Catalog\Setup\CategorySetup */
$installer = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create('Magento\Catalog\Setup\CategorySetup');
/** @var $attribute \Magento\Catalog\Model\ResourceModel\Eav\Attribute */
$attribute = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create(
    'Magento\Catalog\Model\ResourceModel\Eav\Attribute'
);
$attribute->setData(
    [
        'attribute_code' => 'multiselect_attribute',
        'entity_type_id' => $installer->getEntityTypeId('catalog_product'),
        'is_global' => 1,
        'is_user_defined' => 1,
        'frontend_input' => 'multiselect',
        'is_unique' => 0,
        'is_required' => 0,
        'is_searchable' => 0,
        'is_visible_in_advanced_search' => 0,
        'is_comparable' => 0,
        'is_filterable' => 0,
        'is_filterable_in_search' => 0,
        'is_used_for_promo_rules' => 0,
        'is_html_allowed_on_front' => 1,
        'is_visible_on_front' => 0,
        'used_in_product_listing' => 0,
        'used_for_sort_by' => 0,
        'frontend_label' => ['Multiselect Attribute'],
        'backend_type' => 'varchar',
        'backend_model' => 'Magento\Eav\Model\Entity\Attribute\Backend\ArrayBackend',
        'option' => [
            'value' => [
                'option_1' => ['Option 1'],
                'option_2' => ['Option 2'],
                'option_3' => ['Option 3'],
                'option_4' => ['Option 4 "!@#$%^&*'],
            ],
            'order' => [
                'option_1' => 1,
                'option_2' => 2,
                'option_3' => 3,
                'option_4' => 4,
            ],
        ],
    ]
);
$attribute->save();

/* Assign attribute to attribute set */
$installer->addAttributeToGroup('catalog_product', 'Default', 'General', $attribute->getId());