Mock Object Libraries in Java

Question

Would anyone suggest a Mock library and provide the reasoning behind the pick?

I am looking to introduce one to the existing code base.

Thanks.

Answer 1

This is the best comparison I've seen, of multiple Java mocking frameworks, including EasyMock and mockito. [The original page is offline; this link is to an archived copy.]

It includes EasyMock, Mockito, jMock, SevenMock, JMockit, rMock, Unitils.

I used EasyMock first, but have moved to Mockito. Unit tests created with EasyMock were sometimes fragile and hard to debug. Mockito is easy, partly because it distinguishes between stubbing and verification. Here's a Mockito-oriented comparison of it and EasyMock: http://code.google.com/p/mockito/wiki/MockitoVSEasyMock.

Answer 2

My suggestion is JMockit (I wrote it). The project site has a lot of information (and hundreds of actual JUnit tests) comparing several Java mocking APIs (EasyMock, jMock, JMockit, Mockito, PowerMock, Unitils Mock), as well as an extensive feature comparison matrix.