JUnit/Mockito: ArgumentCaptor running before the JUnit test executes? - spring

Question

I have JUnit test such as follows:
#Autowired
MyService myservice;
#Before
public void init() {
myservice.doStuff(new MyObj());
}
#Test
public void test() {
ArgumentCaptor<MyObj> captor = ArgumentCaptor.forClass(MyObj.class);
myservice.doStuff(new MyObj());
verify(myservice, atLeastOnce()).doStuff(captor.capture());
captor.getAllValues(); //this returns 2 - one for the #Before and one for right above
}
As mentioned in the commented code, the captor captures both invocation even though the captor is created after the #Before. Why is this and how can I capture only invocation within the test ?

Answer 1

Something looks wrong in this flow, I'll explain and hopefully this will lead you to the solution:
First of all, ArgumentCaptor is used only with mocks. So myservice has to be a mock,
I was expecting to see something like #MockBean on it or maybe #Mock if you're running a plain mockito test without spring.
Now assuming it is a mock, why would you call a method doStuff on the mock in #Before phase. I can understand if you want to setup some global expectations applicable to all the tests in the class in case you have many, but this seems suspicious to me.
Now, when you use the verify what you actually say is:
Mockito, make sure that my mock myservice called method doStuff (at least once) and for futher verification I would like to "capture" the arguments that were passed to the mock while the method invocation (s).
With this approach its understandable that argument capture gets all the information about all the invocations, and I believe its by design.
To make a point clear, #Before method has nothing to do with mockito, its a purely JUnit hook, so by the time it is called by JUnit framework, all mocks are already inialized and are ready to "record" all the relevant information about everything that the code will do to them (method invocations I mean).