Port tests from convergence simulator

Include the URL of your launchpad blueprint:

https://blueprints.launchpad.net/heat/+spec/convergence-simulator-tests

Problem description

In coming up with the design of convergence, we built a simulator that verifies a substantial number of test scenarios. The scenarios are defined in what amounts to a simple DSL. If we can run the exact same scenarios against the real Heat code base, then we can not only verify that our convergence implementation fullfills the requirements of the simulator but also continue to do that over time, even as we add more scenarios and even if we still have the need to rapidly prototype design changes in the simulator.

Proposed change

Implement a stub for the RPC APIs that puts messages into in-memory queues that are drained by an event loop.

Implement a fake resource type that uses an in-memory store to represent the underlying physical resource.

Provide wrappers for the global inputs to the scenario - reality, verify, Template, RsrcDef, GetRes, GetAtt, engine, converger - that allow them to be backed by the real equivalent classes in Heat.

Finally, reimplement https://github.com/zaneb/heat-convergence-prototype/blob/resumable/test_converge.py using testtools primitives and passing the wrappers above as globals, rather than those defined in https://github.com/zaneb/heat-convergence-prototype/blob/resumable/converge/__init__.py#L24-L41

Alternatives

None

Implementation

Assignee(s)

Primary assignee:
ishant-tyagi

Milestones

Target Milestone for completion:
Kilo-3

Work Items

  • Implement RPC stub and event loop
  • Implement fake TestResource type and backend simulator
  • Implement wrappers to map the scenario DSL to real Heat classes
  • Implement a unit test framework to run the scenarios

Dependencies

Of course, few of these tests are going to pass until Phase 1 of convergence is substantially complete.

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