Mocking and Handling Map.Entry when it is returned from a method call

Question

Summary: I am confused about how to handle a single "Map.Entry" when returned from a method call. In my specific case, I need to mock this (using mockito presently) but my question is as much about how to deal with "Map.Entry" as a single unit than it is about mocking it... Help with both would be greatly appreciated.

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I have a method like the following. I need to create a matching entity (a Map.Entry I assume) for the mock to return when the method is called. I don't know how to create a single Map.Entry. I've traced calls all the way back to the sql call to the db, but can only find a point where the returned Object is cast to a Map.Entry.

No indication of how to build such a thing. I need help with how to build a single "Map.Entry" that can be returned by the mock.

 public Map.Entry<Date,Boolean> getLastModified(SomeClass someClass)
    throws Exception
    {
        return clusterViewDataProvider.getClusterModified(someClass);
    }

Here is a line that would create the mocked object for me. For simplicity, assume that the method above is in the "Foo" class.

Foo foo = mock(Foo.class);

Then I would need something like this to say that when the method is called (as a mock) it should return the "Map.Entry" that I need to build.

when(foo.getLastModifiedGid(any())).thenReturn(the Map.Entry I don't know how to make yet);

Lastly, I need to assert something testable about the Map.Entry that is returned. I'm fine to check the key and value in the assert - nothing fancier than that is required - again, I'm not sure how I'd access this as a single Map.Entry...

assertTrue(The Key == SomeDate)
assertTrue(The Value == True)

If I've been unclear on anything, please comment and I will clarify. Gratzi.

Answer 1

There is no need to create your own Map.Entry implementation. You can use one of the existing implementations like AbstractMap.SimpleEntry:

Date date = new Date();
boolean value = true;

Map.Entry<Date, Boolean> entry =  new AbstractMap.SimpleEntry<>(date, value);
when(foo.getLastModifiedGid(any())).thenReturn(entry);

or AbstractMap.SimpleImmutableEntry :

Map.Entry<Date, Boolean> entry =  new AbstractMap.SimpleImmutableEntry<>(date, value);

As a side note, date classes from java.util are obesolete and classes from java.time should be used for Java 8+. Specifically, java.util.Date is replaced by java.time.Instant.