trait AssertMenuActiveTrailTrait

trait AssertMenuActiveTrailTrait {
    
    /**
     * Assert that active trail exists in a menu tree output.
     *
     * @param array $tree
     *   An associative array whose keys are link paths and whose
     *   values are link titles (not sanitized) of an expected active trail in a
     *   menu tree output on the page.
     * @param bool $last_active
     *   Whether the last link in $tree is expected to be active (TRUE)
     *   or just to be in the active trail (FALSE).
     */
    protected function assertMenuActiveTrail($tree, $last_active) {
        end($tree);
        $active_link_path = key($tree);
        $active_link_title = array_pop($tree);
        $xpath = '';
        if ($tree) {
            $i = 0;
            foreach ($tree as $link_path => $link_title) {
                $part_xpath = !$i ? '//' : '/following-sibling::ul/descendant::';
                $part_xpath .= 'li[contains(@class, :class)]/a[contains(@href, :href) and contains(text(), :title)]';
                $part_args = [
                    ':class' => 'menu-item--active-trail',
                    ':href' => Url::fromUri('base:' . $link_path)->toString(),
                    ':title' => $link_title,
                ];
                $xpath .= $this->buildXPathQuery($part_xpath, $part_args);
                $i++;
            }
            $elements = $this->xpath($xpath);
            $this->assertTrue(!empty($elements), 'Active trail to current page was found in menu tree.');
            // Append prefix for active link asserted below.
            $xpath .= '/following-sibling::ul/descendant::';
        }
        else {
            $xpath .= '//';
        }
        $xpath_last_active = $last_active ? 'and contains(@class, :class-active)' : '';
        $xpath .= 'li[contains(@class, :class-trail)]/a[contains(@href, :href) ' . $xpath_last_active . 'and contains(text(), :title)]';
        $args = [
            ':class-trail' => 'menu-item--active-trail',
            ':class-active' => 'is-active',
            ':href' => Url::fromUri('base:' . $active_link_path)->toString(),
            ':title' => $active_link_title,
        ];
        $elements = $this->xpath($xpath, $args);
        $this->assertTrue(!empty($elements), new FormattableMarkup('Active link %title was found in menu tree, including active trail links %tree.', [
            '%title' => $active_link_title,
            '%tree' => implode(' » ', $tree),
        ]));
    }

}