如何为 if 条件编写此 void 方法的测试用例

Question

public void setRefundIdForPrepaid(RefundReturnRequest refundReturnRequest) { 
    if(StringUtils.isBlank (refundReturnRequest.getRefundRequest().getRefundId())) {
        refundReturnRequest.getRefundRequest().setRefundId (Integer.toString(ThreadLocalRandom.current().nextInt(999999999)));
    }
}

Answer 1

you can test the RefundReturnRequest refundReturnRequest after the method executed.

@Test
void testSetRefundIdForPrepaid(){
   //build param
   RefundReturnRequest refundReturnRequest = new RefundReturnRequest();
   //executetd
   service.setRefundIdForPrepaid(refundReturnRequest);
   //test result
   assertThat(refundReturnRequest.getRefundRequest().getRefundId()).isEqualTo(xxx);
}

Answer 2

You could make RefundReturnRequest a Spy and verify that the set was called. If you want to test it further you could pass on an Argument Captor and check that the random number is between a certain range. But this is type of method that I don't see much value in testing. If you wanna just write 2 test cases for the If logic just verify the set method has been called and another test where it hasn't been called.

So you'll need a Mock refundReturnRequest that returns a Spy RefundRequest after getRefundRequest is called. And verify the setter.

Answer 3

@Test
void TestsetRefundIdForPrepaid(){
//test case
}