How do I mock a class marked final and has a private constructor using jMockit

Question

I would like to write some state based tests using JMockit to mock up CSVRecord . The problem is that CSVRecord is final (which means I have to use a mocking framework like JMockit ) and CSVRecord's constructor has package private visibility.

Since it is package private, I can't call new CSVRecord(arg, arg, ...) , which means I can never I instantiate my mock. Its parent, CSVParser, is the only class that can create an instance.

Does JMockit have a way to deal with this scenario?

note: JMockit or Mockito are the only frameworks we use on this project. No other framework will be acceptable. My preference is to use a MockUp.

Answer 1

If it is just a matter of calling the private constructor, then yes, JMockit has tools to deal with that. See the tutorial

Answer 2

It sounds more like CSVRecord isn't a good candidate for mocking. If possible, tests targetting another public class which uses it internally would be preferable.

Otherwise, JMockit provides a Deencapsulation class with newInstance methods.

As a side note, Mockito only supports behavior-based tests; JMockit provides "mock-ups" ( MockUp ), but it's not the same as writing a pure state-based black box test.

Answer 3

Use:

ConstructorReflection.newInstance

in newer versions of Jmockit.