I typically avoided using e.g. assertIsNone() thinking we couldn't use
it on 2.7, but now that we use testtools.TestCast there are a bunch of
useful assertion methods we can use.
Change-Id: I7696dc4744cdfd2466773326f202bc08dcfcbf0f
These are pretty comprehensive tests for the exception serialization
code. The code itself code do with a bunch of refactoring, but that will
come later.
The main TODO item is that we need a way for users of the API to
register the list of modules that it wants to allow exceptions to be
deserialized from. There is no need for this to be an end-user
configuration option, but we do need each service to be able to specify
its own list.
Change-Id: Ib2fc3f1ca5da708b41bdc00e8ac6ce0c92399ce8
