public function testAddLiteralToSequence()
{
$testSubject = 'http://some/subject/s1';
$testObject1 = 'foo1';
$testObject2 = 'foo2';
$graph = new ExtendedGraph();
$graph->add_literal_to_sequence($testSubject, $testObject1);
$objects = $graph->get_sequence_values('http://some/subject/s1');
$this->assertEquals(array($testObject1), $objects);
$graph->add_literal_to_sequence($testSubject, $testObject2);
$objects = $graph->get_sequence_values('http://some/subject/s1');
$this->assertEquals(array($testObject1, $testObject2), $objects);
$graph->add_literal_to_sequence('http://some/other/subject', 'bar');
$objects = $graph->get_sequence_values('http://some/subject/s1');
$this->assertEquals(array($testObject1, $testObject2), $objects);
$objects = $graph->get_sequence_values('http://some/other/subject');
$this->assertEquals(array('bar'), $objects);
}