storageMock = $this ->getMockBuilder(\Magento\Framework\Session\StorageInterface::class) ->setMethods(['setQuoteId']) ->getMockForAbstractClass(); $this->objectManager = new ObjectManager($this); $this->session = $this->objectManager->getObject( \Magento\Authorizenet\Model\Directpost\Session::class, [ 'storage' => $this->storageMock, ] ); } public function testSetQuoteId() { $quoteId = 1; $this->storageMock->expects($this->once()) ->method('setQuoteId') ->with($quoteId); $this->assertInstanceOf( \Magento\Authorizenet\Model\Directpost\Session::class, $this->session->setQuoteId($quoteId) ); } }