JUnit tests: Suppress enum constructor by mocking?

Question

I know that it is possible to mock a single enum(using How to mock an enum singleton class using Mockito/Powermock?), but I have like 1000 of enum values and they can call 5 different constructors. The enum values are often changing in development.

I want to really mock only one or two for my JUnit test. I don't care about the rest, but they are still instantiated, which calls some nasty stuff, which loads the values for the enum from the file system.

Yes I know It's very bad design. But for now I don't get the time to change it.

At the moment we have Mockito/powermock in use. But any framework, which can solve this sh** I mean bad design is welcome.

Let's say I have an enum similar to this:

public static enum MyEnum {
   A(OtherEnum.CONSTANT),
   B("1"),
   C("1", OtherEnum.CONSTANT),
   //...and so on for again 1000 enum values :(

   private double value;
   private String defaultValue;
   private OtherEnum value;

   /* Getter/Setter */
   /* constructors */
}

One quick fix might be to have the `enum` implement an `interface` that can then be mocked. It's a hack but would allow you to write your test now, then you should refactor — Nick Holt, Mar 12 '14 at 09:38
Have a look at [JMockit](https://code.google.com/p/jmockit/). — Martin Schröder, Mar 12 '14 at 15:23

score 1 · Answer 1 · answered Mar 18 '14 at 21:00

1

I agree with Nick-Holt who suggested adding an interface:

 public interface myInterface{

     //add the getters/setters you want to test

 }

public enum MyEnum implements MyInterface{

    //no changes needed to the implementations
    //since they already implement the methods you want to use

}

Now you can use the normal mock abilities of Mockito without having to rely on Powermock

MyInterface mock = Mockito.mock(MyInterface.class);
when(mock.foo()).thenReturn(...);
//..etc

answered Mar 18 '14 at 21:00

dkatzel

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How can I suppress calling the constructor of the enum? Is it similar to that call? My experience with mockito is limited. – keiki Mar 24 '14 at 10:02
If you go with the interface route, then the enum isn't used at all so the constructor isn't called. – dkatzel Mar 24 '14 at 14:03
So if somewhere in the code Enumclass.ENUM.isEnabled() is called is this possible to be suppresed? – keiki Mar 24 '14 at 14:13
I tried and didn't work for me as we.. @keiki were you able to figure out how to do it? – Shruts_me Apr 17 '17 at 00:50
@Shruts_me Not really. We are actually calling one of those setters now :( – keiki Apr 18 '17 at 12:28

JUnit tests: Suppress enum constructor by mocking?

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