Creates random content as an update based on node content type.
string $type: Node content type (e.g., 'article').
array Random content needed by various node types.
private function getContentUpdate($type) {
$langcode = Language::LANGCODE_NOT_SPECIFIED;
$content = array(
"body[{$langcode}][0][value]" => $this
->randomName(32),
);
return $content;
}