Check if a field storage entity was created for the paragraph fields.
string $entity_type: The entity type to check on.
string $field_name: The field name to check for.
protected function assertParagraphFieldExists($entity_type, $field_name) {
$field_storage = FieldStorageConfig::loadByName($entity_type, $field_name);
$this
->assertNotNull($field_storage);
$this
->assertEquals('entity_reference_revisions', $field_storage
->getType());
$this
->assertEquals('paragraph', $field_storage
->getSetting('target_type'));
}