public function testFromGraph()
{
$itemUri = 'http://foo/item';
$mainResourceUri = 'http://foo/mainResource';
$partOfResourceUri = 'http://foo/partOfResource';
$itemGraph = new ExtendedGraph();
$itemGraph->add_resource_triple($itemUri, ExtendedGraph::rdf . 'type', self::ONT_resource . 'Item');
$itemGraph->add_resource_triple($itemUri, self::ONT_resource . 'resource', $mainResourceUri);
$graph = new ExtendedGraph();
$graph->from_graph($itemGraph);
$this->assertTrue($graph->is_equal_to($itemGraph));
}