Sanpi\Behatch\Context\XmlContext::theXmlAttributeShouldExist PHP Method

    public function theXmlAttributeShouldExist($attribute, $element)
    {
        $elements = $this->theXmlElementShouldExist("{$element}[@{$attribute}]");
        $actual = $elements->item(0)->getAttribute($attribute);
        if (empty($actual)) {
            throw new \Exception("The attribute value is '{$actual}'");
        }
        return $actual;
    }