Add missing return statements to decorators.
Rename decorator to register.
Split long line in two.
Remove package prefixes in tests.
Remove cache argument from factory decorator.
Use mocks to test the decorators.
Add more tests for decorators.
Use pass if return value is not tested.
Use alternative as an alternative name in test.
Add test for method to register a factory.
Add test for method to register a service.
Add mock as a requirement for travis.