How to mock the return value of a Map?

Question

I have code that looks like so:

for (Map.Entry<Integer, Action> entry : availableActions.entrySet()) {
  ...
}

I've tried to mock it like this:

Map mockAvailableActions = mock(Map.class, Mockito.RETURNS_DEEP_STUBS);
mockAvailableActions.put(new Integer(1), mockAction);

I would think that would be enough. But entrySet is empty. So I added this:

when(mockAvailableActions.entrySet().iterator()).thenReturn(mockIterator);
when(mockIterator.next()).thenReturn(mockAction);

Still entrySet is empty. What am I doing wrong? Thanks for any input!

codebox · Accepted Answer · 2017-05-31T07:14:51.480

31

Perhaps I'm missing something, but why not just do this:

Map.Entry<Integer, Action> entrySet = <whatever you want it to return>
Map mockAvailableActions = mock(Map.class);
when(mockAvailableActions.entrySet()).thenReturn(entrySet);

Also consider whether you actually need a mock Map at all, wouldn't a real one do the job? Mocks are usually used to replace other pieces of your code which you don't want to be involved in your unit test, a Map is part of the core Java language and isn't usually mocked out.

edited May 31 '17 at 07:14

answered Apr 04 '13 at 19:34

codebox

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Yes, that was my first thought. But what would "Map.Entry entrySet =" look like? Entry can't be instantiated, so I would I define the variable? – CNDyson Apr 04 '13 at 19:47
http://stackoverflow.com/questions/3110547/java-how-to-create-new-entry-key-value – Garrett Hall Apr 04 '13 at 20:00
4

You were right Codebox - this answer was not to mock the Map at all. – CNDyson Apr 04 '13 at 20:52

How to mock the return value of a Map?

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