How to verify static void method has been called with power mockito

Question

I am using the following   Powermock-mockito 1 5 12 Mockito 1 95 junit 4 11   Here is my utils class  public void InternalUtils       public static void sendEmail String from  String   to  String msg  String body              here is gist of the class under test   public class InternalService          public void processOrder Order order               if  order isSuccessful                     InternalUtils sendEmail                                 And here is the test    PrepareForTest  InternalUtils class    RunWith PowerMockRunner class  public class InternalService      public void verifyEmailSend             mockStatic Internalutils class           doNothing   when InternalUtils   sendEmail   anyString    any String class   anyString    anyString             Order order   mock Order class           when order isSuccessful    thenReturn true           InternalService is   new InternalService             verifyStatic times 1            is processOrder order            The above test fails  The verification mode given is none  but according to the code  if order is successful than email must be send

User · Answer

Thou the above answer is widely accepted and well documented, I found some of the reason to post my answer here :-

    doNothing().when(InternalUtils.class); //This is the preferred way
                                           //to mock static void methods.
    InternalUtils.sendEmail(anyString(), anyString(), anyString(), anyString());

Here, I dont understand why we are calling InternalUtils.sendEmail ourself. I will explain in my code why we don't need to do that.

mockStatic(Internalutils.class);

So, we have mocked the class which is fine. Now, lets have a look how we need to verify the sendEmail(/..../) method.

@PrepareForTest({InternalService.InternalUtils.class})
@RunWith(PowerMockRunner.class)
public class InternalServiceTest {

    @Mock
    private InternalService.Order order;

    private InternalService internalService;

    @Before
    public void setup() {
        MockitoAnnotations.initMocks(this);
        internalService = new InternalService();
    }

    @Test
    public void processOrder() throws Exception {

        Mockito.when(order.isSuccessful()).thenReturn(true);
        PowerMockito.mockStatic(InternalService.InternalUtils.class);

        internalService.processOrder(order);

        PowerMockito.verifyStatic(times(1));
        InternalService.InternalUtils.sendEmail(anyString(), any(String[].class), anyString(), anyString());
    }

}

These two lines is where the magic is, First line tells the PowerMockito framework that it needs to verify the class it statically mocked. But which method it need to verify ?? Second line tells which method it needs to verify.

PowerMockito.verifyStatic(times(1));
InternalService.InternalUtils.sendEmail(anyString(), any(String[].class), anyString(), anyString());

This is code of my class, sendEmail api twice.

public class InternalService {

    public void processOrder(Order order) {
        if (order.isSuccessful()) {
            InternalUtils.sendEmail("", new String[1], "", "");
            InternalUtils.sendEmail("", new String[1], "", "");
        }
    }

    public static class InternalUtils{

        public static void sendEmail(String from, String[]  to, String msg, String body){

        }

    }

    public class Order{

        public boolean isSuccessful(){
            return true;
        }

    }

}

As it is calling twice you just need to change the verify(times(2))... that's all.

User · Answer

If you are mocking the behavior  with something like doNothing    there should really be no need to call to verify     That said  here s my stab at re-writing your test method    PrepareForTest  InternalUtils class    RunWith PowerMockRunner class  public class InternalServiceTest     Note the renaming of the test class     public void testProcessOrder               Variables         InternalService is   new InternalService            Order order   mock Order class              Mock Behavior         when order isSuccessful    thenReturn true           mockStatic Internalutils class           doNothing   when InternalUtils class     This is the preferred way                                                  to mock static void methods          InternalUtils sendEmail anyString    anyString    anyString    anyString                Execute         is processOrder order                          Verify         verifyStatic InternalUtils class     Similar to how you mock static methods                                              this is how you verify them          InternalUtils sendEmail anyString    anyString    anyString    anyString              I grouped into four sections to better highlight what is going on   1  Variables  I choose to declare any instance variables   method arguments   mock collaborators here  If it is something used in multiple tests  consider making it an instance variable of the test class   2  Mock Behavior  This is where you define the behavior of all of your mocks  You re setting up return values and expectations here  prior to executing the code under test  Generally speaking  if you set the mock behavior here you wouldn t need to verify the behavior later   3  Execute  Nothing fancy here  this just kicks off the code being tested  I like to give it its own section to call attention to it   4  Verify  This is when you call any method starting with verify or assert  After the test is over  you check that the things you wanted to have happen actually did happen  That is the biggest mistake I see with your test method  you attempted to verify the method call before it was ever given a chance to run  Second to that is you never specified which static method you wanted to verify   Additional Notes  This is mostly personal preference on my part  There is a certain order you need to do things in but within each grouping there is a little wiggle room  This helps me quickly separate out what is happening where   I also highly recommend going through the examples at the following sites as they are very robust and can help with the majority of the cases you ll need    https   github com powermock powermock wiki Mockito  PowerMock Overview   Examples  http   site mockito org mockito docs current org mockito Mockito html  Mockito Overview   Examples

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