Tempest Field Guide to Scenario tests
=====================================


What are these tests?
---------------------

Scenario tests are "through path" tests of OpenStack
function. Complicated setups where one part might depend on completion
of a previous part. They ideally involve the integration between
multiple OpenStack services to exercise the touch points between them.

An example would be: start with a blank environment, upload a glance
image, deploy a vm from it, ssh to the guest, make changes, capture
that vm's image back into glance as a snapshot, and launch a second vm
from that snapshot.


Why are these tests in tempest?
-------------------------------
This is one of tempests core purposes, testing the integration between
projects.


Scope of these tests
--------------------
Scenario tests should use the official python client libraries for
OpenStack, as they provide a more realistic approach in how people
will interact with the services.

Tests should be tagged with which services they exercise, as
determined by which client libraries are used directly by the test.


Example of a good test
----------------------
While we are looking for interaction of 2 or more services, be
specific in your interactions. A giant "this is my data center" smoke
test is hard to debug when it goes wrong.

A flow of interactions between glance and nova, like in the
introduction, is a good example. Especially if it involves a repeated
interaction when a resource is setup, modified, detached, and then
reused later again.