Mockito mock object with list argument's contents

Question

I've faced this situation pretty often and don't know how to resolve it using Mockito's default methods such as (any, anyList, eq)

For example I have an object where I want to mock a method expecting a list which contains other mocked objects. Let me explain:

public class MyMapper {
   public List<DataObjects> convertList(List<String> rawContents) {
      rawContents.stream().map(r -> convertObject(r))
      .collect(Collectors.toList());
   }

   public DataObject convertObject(String rawContent) {
       return new DataObject(rawContent);
   }
} 

public class MyWorkerClass {
     public boolean start(List<String> rawContents) {
           List<DataObject> objects = new MyMapper().convertList(rawContents);
           return publish(objects);
     }

     public boolean result publish(List<DataObject> objects) {
           ../// some logic
     }
}

Now what I want to assert is something like. Note: Please assume the right mocks are returned when new() is called [Using some PowerMockito]

@Test
public void test() {
   String content = "content";
   DataObject mock1 = Mockito.mock(DataObject.class);
   MyMapper mapperMock = Mockito.mock(MyMapper.class);
   MyWorkerClass worker = new MyWorkerClass();

   Mockito.when(mapperMock.convertObject(content)).thenReturn(mock1);

   Mockito.when(worker.publish(eq(Arrays.asList(mock1)).thenReturn(true);

   boolean result = worker.start(Arrays.asList(content));
   Assert.assertTrue(result);
}

The problem with the code above is in the line

  Mockito.when(worker.publish(eq(Arrays.asList(mock1)).thenReturn(true);

This will try to match the list object instead of the list contents, in other words, even when I have to lists A: [mock1] and B: [mock1], A is not equal to B and ultimately the stubbing fails.

What I need is some sort of matcher similar to hamcrest's contain matcher. Something like:

  Mockito.when(worker.publish(contains(mock1)).thenReturn(true));

Is there anyway I can achieve this? Keep in mind the code above is just an example to grasp the problem, the real situation is a little bit more complex and I can only mock individual objects, not the list itself

Thanks

No, that's not the problem. The problem is that MyWorkerClass creates its own instance of MyMapper and the n uses it. it doesn't use the mock MyMapper that your test creates. The code doesn't compile, too. And you're trying to mock a method of a real object (worker). Post a real, compiling example that actually reproduces the problem. — JB Nizet, Aug 08 '18 at 18:21
As I said, the code is just a reference. You can assume there is some extra PowerMockito stubbing going on to return the right mocks on new MyWorkerClass() — Pablo, Aug 08 '18 at 18:29
The problem is that if I need to assume something different on half of your lines of code, it's pretty hard to guess what the actual problem is. So, again, post a real, compiling example that actually reproduces the problem. — JB Nizet, Aug 08 '18 at 18:31

score 2 · Answer 1 · answered Aug 08 '18 at 19:19

Nevermind, later I learned that Mockito's eq() method will call the equals() method on the argument. Now if that is an ArrayList it means it will return true if two list sizes are equal and if the equal's comparison for each one of the elements in the list also returns true. See https://docs.oracle.com/javase/6/docs/api/java/util/List.html#equals%28java.lang.Object%29

And for even more customization argThat() could be used What's the difference between Mockito Matchers isA, any, eq, and same?

Mockito mock object with list argument's contents

1 Answers1