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()); }