public function testBackground()
{
$oStub = $this->getMockForAbstractClass('PhpOffice\\PhpPresentation\\Slide\\AbstractBackground');
$object = new Slide();
$this->assertNull($object->getBackground());
$this->assertInstanceOf('PhpOffice\\PhpPresentation\\Slide', $object->setBackground($oStub));
$this->assertInstanceOf('PhpOffice\\PhpPresentation\\Slide\\AbstractBackground', $object->getBackground());
$this->assertInstanceOf('PhpOffice\\PhpPresentation\\Slide', $object->setBackground());
$this->assertNull($object->getBackground());
}