proposal for tempest directory restructure

This is the text of a proposal for tempest directory restructure,
largely coming out of OpenStack summit. Once this has gotten core
sign off, I'llstart implementing the refactors into those
directories, and each will have a more specific README explaining
good tests in that kind of environment.

This proposal doesn't attempt to layout structure for tests we
don't have yet, this is entirely about organizing what we have into
something easier to understand. It is assumed new classes of tests
will get proposed over time, and we'll take them as they come.

Part of bp:tempest-repo-restructure

Change-Id: Ib8c55602b085622d322676ba2c24d9719fb9737d

tempest/README.rst

@@ -0,0 +1,98 @@
+Tempest Field Guide
+-----------
+
+Tempest is designed to be useful for a large number of different
+environments. This includes being useful for gating commits to
+OpenStack core projects, being used to validate OpenStack cloud
+implementations for both correctness, as well as a burn in tool for
+OpenStack clouds.
+
+As such Tempest tests come in many flavors, each with their own rules
+and guidelines. Below is the proposed Havana restructuring for Tempest
+to make this clear.
+
+tempest/
+   3rdparty/ - 3rd party api tests
+   api/ - API tests
+   cli/ - CLI tests
+   scenario/ - complex scenario tests
+   stress/ - stress tests
+   whitebox/ - white box testing
+
+Each of these directories contains different types of tests. What
+belongs in each directory, the rules and examples for good tests, are
+documented in a README.rst file in the directory.
+
+
+3rdparty
+------------
+
+Many openstack components include 3rdparty API support. It is
+completely legitmate for Tempest to include tests of 3rdparty APIs,
+but those should be kept seperate from the normal OpenStack
+validation.
+
+TODO: tempest/tests/boto should become tempest/3rdparty/boto
+
+
+api
+------------
+
+API tests are validation tests for the OpenStack API. They should not
+use the existing python clients for OpenStack, but should instead use
+the tempest implementations of clients. This allows us to test both
+XML and JSON. Having raw clients also lets us pass invalid JSON and
+XML to the APIs and see the results, something we could not get with
+the native clients.
+
+When it makes sense, API testing should be moved closer to the
+projects themselves, possibly as functional tests in their unit test
+frameworks.
+
+TODO: The bulk of tempest/tests should move to tempest/api
+
+
+cli
+------------
+
+CLI tests use the openstack CLI to interact with the OpenStack
+cloud. CLI testing in unit tests is somewhat difficult because unlike
+server testing, there is no access to server code to
+instantiate. Tempest seems like a logical place for this, as it
+prereqs having a running OpenStack cloud.
+
+TODO: the top level cli directory moves to tempest/cli
+
+
+scenario
+------------
+
+Scenario tests are complex "through path" tests for OpenStack
+functionality. They are typically a series of steps where complicated
+state requiring multiple services is set up exercised, and torn down.
+
+Scenario tests can and should use the OpenStack python clients.
+
+TODO: tests/network/test_network_basic_ops.py,
+tests/compute/servers/*_ops.py should move to tempest/scenario (others)
+
+
+stress
+-----------
+
+Stress tests are designed to stress an OpenStack environment by
+running a high workload against it and seeing what breaks. Tools may
+be provided to help detect breaks (stack traces in the logs).
+
+TODO: old stress tests deleted, new_stress that david is working on
+moves into here.
+
+
+whitebox
+----------
+
+Whitebox tests are tests which require access to the database of the
+target OpenStack machine to verify internal state after opperations
+are made. White box tests are allowed to use the python clients.
+
+TODO: collect out whitebox tests to this location.