Extending / Mocking enums

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Mocking Java enum to add a value to test fail case

I have a switch statement that works on an enum. The "default" case of the switch is to throw a runtime exception. It's coded like this to trap the situation where someone adds a value to the enum but forgets to update the switch statement.

I want to test this execution path, but I am struggling to find a way of doing so without putting an unused enum value into my live code. Is this a misuse of enum, or is there an accepted way of writing this test?

Please look at this: http://stackoverflow.com/questions/5323505/mocking-java-enum-to-add-a-value-to-test-fail-case — exception, Jun 11 '12 at 14:31
Are you inclined to use any mocking frameworks like Mockito? — exception, Jun 11 '12 at 14:31
Mokito can't do it afaik - but it looks like PowerMock might be the answer - I'll look in to it. Thanks — DaveH, Jun 11 '12 at 14:35
PowerMock works like a charm - thanks very much for the suggestion. — DaveH, Jun 11 '12 at 15:21

score 1 · Answer 1 · answered Jun 11 '12 at 14:17

1

What I am thinking you could do to test this is have a test case where you basically get all values of your enum like

T[] allEnumValues = enumValue.getDeclaringClass().getEnumConstants();

or

T[] allEnumValues = enumType.values();

and then take each one and put it in the switch statement. If you get an exception you have a problem.

PS: Link to the getEnumConstants() method.

answered Jun 11 '12 at 14:17

This isn't quite what I want but is an interesting approach. I actually WANT to pass in an enum value that does not exist in the switch statement so that I can prove that the RTE is thrown. ( My client is very keen on code coverage ..... ) – DaveH Jun 11 '12 at 14:27

Extending / Mocking enums

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