Magento2 - Unittest with Object manager

As much as possible avoid using object manager to create object on magento if your going to create unittest on it. Use the Factory instead but in some case some plugins(Unirgy) love the object manager. Then when you override there class you will getting headache on creating unittest.

One of the error you will encounter was

"Expectation failed for method name is equal to <string:create> when invoked zero or more times" this  happen  you call create method  multiple times.

Sample:

 /** @var \Winz\Sales\Api\Data\OrderInvoiceResultInterface */
$orderInvoiceResultInterface = $this->getMockBuilder('Winz\Sales\Api\Data\OrderInvoiceResultInterface')
    ->disableOriginalConstructor()              
    ->setMethods(['setOrder', 'setInvoice', 'getOrder', 'getInvoice', ])
    ->getMock();      
$orderInvoiceResult = $objectManagerInterface
    ->expects($this->any())
    ->method('create')
    ->with('Storm\Sales\Api\Data\OrderInvoiceResultInterface')
    ->willReturn($orderInvoiceResultInterface);
/** @var \Winz\Sales\Api\Data\OrderResultInterface */
$orderResultInterface = $this->getMockBuilder('Winz\Sales\Api\Data\OrderResultInterface')
    ->disableOriginalConstructor()
    ->setMethods(['setId', 'setNo', 'getId', 'getNo'])
    ->getMock();      
$orderResult = $objectManagerInterface
    ->expects($this->once())
    ->method('create') 
  ->with('Winz\Sales\Api\Data\OrderResultInterface')
    ->willReturn($orderResultInterface);

Fixed of the above code.

$orderResultInterface = $this->getMockBuilder('Storm\Sales\Api\Data\OrderResultInterface')
    ->disableOriginalConstructor()
    ->getMock();
$orderInvoiceResultInterface = $this->getMockBuilder('Winz\Sales\Api\Data\OrderInvoiceResultInterface')
    ->disableOriginalConstructor()              
    ->setMethods(['setOrder', 'setInvoice', 'getOrder', 'getInvoice', ])
    ->getMock();      
$objectManagerInterface
    ->expects($this->any())
    ->method('create')
    ->withConsecutive(
            ['Storm\Sales\Api\Data\OrderResultInterface'],
            ['Storm\Sales\Api\Data\OrderInvoiceResultInterface']
    )
    ->willReturnOnConsecutiveCalls(
            $this->returnValue($orderResultInterface),
            $this->returnValue($orderInvoiceResultInterface)
    );