An advantage of consuming keystoneauth is that the application doesn't
need to know the details of the authentication sequence to use the
library. Currently in testing they are having to provide a specific auth
plugin and this means their tests execute this full auth sequence and
they have to mock that out.
Create a SimpleTestPlugin that has the standard values that an
application might be interested in. This can be used in testing instead
of a real plugin to remove any network interaction and simplify the
authentication component so applications can focus on their problems.
We then create 2 fixtures that will mock out functions to load the
SimpleTestPlugin instead of a real plugin in application code.
The SimpleLoaderFixture will mock out all calls to keystoneauth plugin
loading and return the basic plugin, which is going to be sufficient for
testing for most applications.
The SimplePluginFixutre will mock out a specific function and return a
SimpleTestPlugin so that applications can mock out just a specific
section of loading code.
Change-Id: Ica852dcbd89323b23f1681403f8c57b5399bf4e7
d545c4e97d