Testing and Mocking

JUnit

Surefire

Plugin to run JUnit with maven

Mockito

Mocking

Problem:

• a handler calls several remote services during the handling

  • must mock remote calls

• the handler uses Guice to wiring up the objects

  • in order to test DI setup, wish to use production code bootstrap process - using Guice - instead of instantiating class with all-args-constructor and provide fakes

So to summarise - need to create the handler as if in production, with Guice wiring up everything in behind, but somehow intercept the remote calls

Solution:

Guice configuration uses Modules.

In a maven setup, just create a Module class with the same package and class name in test folder - so to override the same class in main folder. This is a simple and sure way to replace a class with a mock.

To intercept network, just provide a mock http client through the replaced module.

Failed Attempts:

PowerMock:

• yes it can intercept object construction

• however when involves a complex graph - interfaces, extends and abstract classes, it does not work. Guess is maybe the constructor is not attached to the implementation class but to the parent (abstract) class.