public function testMaterialsInMultimediaObject()
{
$mm = new MultimediaObject();
$material1 = new Material();
$material2 = new Material();
$material3 = new Material();
$this->assertEquals(0, count($mm->getMaterials()));
$mm->addMaterial($material1);
$mm->addMaterial($material2);
$mm->addMaterial($material3);
$this->assertEquals(3, count($mm->getMaterials()));
$materialsArray = array($material1, $material2, $material3);
$this->assertEquals($materialsArray, $mm->getMaterials()->toArray());
$mm->removeMaterial($material2);
$this->assertEquals(2, count($mm->getMaterials()));
$this->assertTrue($mm->containsMaterial($material1));
$this->assertFalse($mm->containsMaterial($material2));
$materialsArray = array(0 => $material1, 2 => $material3);
$this->assertEquals($materialsArray, $mm->getMaterials()->toArray());
}