Open Stack

Summary - In puppet module spec tests, do not use "stubs", which means 
the method will be called 0 or more times.  Instead, use "expects", 
which means the method must be called exactly 1 time, or some other more 
fine grained expectation method stubber.

Our puppet unit tests mostly use rspec, but use Mocha 
http://gofreerange.com/mocha/docs/index.html for object mocking and 
method stubbing.

I have already run into several cases where the spec test result is 
misleading because "stubs" was used instead of "expects", and I have 
spent a lot of time trying to figure out why a method was not called, 
because adding an expectation like

           provider.class.stubs(:openstack)
                         .with('endpoint', 'list', '--quiet', 
'--format', 'csv', [])
                         .returns('"ID","Region","Service Name","Service 
Type","Enabled","Interface","URL"
"2b38d77363194018b2b9b07d7e6bdc13","RegionOne","keystone","identity",True,"admin","http://127.0.0.1:5002/v3"
"3097d316c19740b7bc866c5cb2d7998b","RegionOne","keystone","identity",True,"internal","http://127.0.0.1:5001/v3"
"3445dddcae1b4357888ee2a606ca1585","RegionOne","keystone","identity",True,"public","http://127.0.0.1:5000/v3"
')

implies that "openstack endpoint list" will be called.

If at all possible, we should use an explicit expectation.  For example, 
in the above case, use "expects" instead:

           provider.class.expects(:openstack)
                         .with('endpoint', 'list', '--quiet', 
'--format', 'csv', [])
                         .returns('"ID","Region","Service Name","Service 
Type","Enabled","Interface","URL"
"2b38d77363194018b2b9b07d7e6bdc13","RegionOne","keystone","identity",True,"admin","http://127.0.0.1:5002/v3"
"3097d316c19740b7bc866c5cb2d7998b","RegionOne","keystone","identity",True,"internal","http://127.0.0.1:5001/v3"
"3445dddcae1b4357888ee2a606ca1585","RegionOne","keystone","identity",True,"public","http://127.0.0.1:5000/v3"
')

This means that "openstack endpoint list" must be called once, and only 
once.  For odd cases where you want a method to be called some certain 
number of times, or to return different values each time it is called, 
the Expectation class 
http://gofreerange.com/mocha/docs/Mocha/Expectation.html should be used 
to modify the initial expectation.

Unfortunately, I don't think we can just do a blanket 
"s/stubs/expects/g" in *_spec.rb, without incurring a lot of test 
failures.  So perhaps we don't have to do this right away, but I think 
future code reviews should -1 any spec file that uses "stubs" without a 
strong justification.