public function testBeforeSave()
{
$object = $this->getMockBuilder('Magento\\Framework\\Object')->disableOriginalConstructor()->setMethods(array('getDefaultBilling', 'unsetDefaultBilling'))->getMock();
$object->expects($this->once())->method('getDefaultBilling')->will($this->returnValue(null));
$object->expects($this->once())->method('unsetDefaultBilling')->will($this->returnSelf());
/** @var \Magento\Framework\Object $object */
$this->testable->beforeSave($object);
}