The ActivitiTestCase provides an easy way to unit test process definitions. However, if the process definition uses expressions to reference beans (e.g. Spring or CDI beans), additional configuration is needed for Activiti to resolve those beans. One solution is to start a test context that contains the referenced beans or fakes that replace them in a test environment (like the SpringActivitiTestCase does). Alternatively, the beans could be mocked using a mock framework like mockito.
For this to work, we need to add a MockExpressionManager and MockElResolver.