On Wed, Jan 17, 2018 at 4:47 PM, Cleber Rosa <cr...@redhat.com> wrote: > > > On 01/17/2018 06:41 PM, Alistair Francis wrote: >> On Wed, Jan 17, 2018 at 12:05 AM, Cleber Rosa <cr...@redhat.com> wrote: >>> TL;DR >>> ===== >>> >>> This is about how QEMU developers can get started with functional >>> tests that are built on top of the Avocado libraries (and meant to be >>> run with the Avocado test runner). >>> >>> The past >>> ======== >>> >>> The Avocado project[1] has been working, for quite some time now, on a >>> "set of tools and libraries" with the goal of making writing tests >>> easier. It is supposed to be a framework agnostic to the exact >>> software that will be under test. >>> >>> But, at the same time, the Avocado project cannot deny its inheritance >>> and influences. Those come from Autotest[2], which had "KVM Autotest" >>> as its largest and most developed "test". This large Autotest test >>> (KVM Autotest) became virt-test[3] and later got integrated into >>> Avocado and became Avocado-VT[4] which is quite relevant here, >>> together with its QEMU test provider[5]. >>> >>> Avocado-VT and the QEMU test provider attempt to provide coverage >>> across platform and QEMU versions, which increases its complexity. >>> Also, it's built on a legacy set of principles and tools that makes >>> some developers stir away from it. >>> >>> What's new? >>> =========== >>> >>> A few months ago, the Avocado developers returned to its >>> "virtualization origins", in an attempt to learn from the QEMU >>> project, and try to help with a way to have more functional tests in >>> the upstream QEMU repo. >>> >>> We believe it's possible to expand the test coverage for QEMU by >>> facilitating >>> the creation of more functional tests QEMU. This is no different than how >>> other types of tests are already included in the tree itself. >>> >>> How >>> === >>> >>> How we did it (so far) >>> ---------------------- >>> >>> We're aware that there's a dilemma here: to be able to easily write >>> more powerful tests, a lot of the complexity has to be moved >>> elsewhere. Here, it means moving complexity from the test itself to a >>> framework. The QEMU source tree itself has proofs of this approach, >>> being the "scripts" and "tests/qemu-iotests" some of the examples. >>> >>> Avocado itself[1] provides a lot of the code that should help to >>> absorb some of the complexities in writing tests, but not exactly >>> everything that is needed for QEMU. The approach we believe will have >>> the best balance is to reuse upstream Avocado libraries whenever they >>> are useful and generic enough, and on top of that, libraries that are >>> part of QEMU itself. >>> >>> How can you get started with it >>> ------------------------------- >>> >>> First of all, get Avocado installed. Besides the Avocado test runner >>> itself, this will give you the basic libraries on which the other part >>> of this work was built on. We want that to be simple and painless, so >>> here's our best bet for a one-liner installation: >>> >>> pip install --user avocado-framework >>> avocado-framework-plugin-varianter-yaml-to-mux aexpect >>> >>> That will install Avocado within the user's home directory. If you >>> give up on it, it can be uninstalled with another simple one-liner: >>> >>> pip uninstall -y avocado-framework >>> avocado-framework-plugin-varianter-yaml-to-mux aexpect >>> >>> Now, suppose you're working on a given feature, and want to try your >>> luck writing a test using this work. To avoid having you fetching and >>> rebasing from our currently in development fork[6] and branch[7], you >>> can just >>> add one commit to your tree with: >>> >>> curl >>> https://patch-diff.githubusercontent.com/raw/apahim/qemu/pull/17.patch | >>> git am - >>> >>> This will get a simple patch from a snapshot branch[8]. You can, of course, >>> do it "the git way", fetching from that repo[6] and using the >>> non-snapshotted branch. >>> >>> After that, we'd love for you to take a look at some of the existing >>> tests[9][10] and then attempt to create test for your own use case. >>> The basic README[11] file, and the Avocado documentation[12] are also >>> important resources not to be missed. >>> >>> What's next? >>> ============ >>> >>> Initially, feedback is what we're looking for. It would be greatly >>> appreciated to understand if/how this suits (or not) use cases out >>> there. >>> >>> After feedback, further refinements, and more tests are written, the >>> Avocado developers will follow up with an initial patch series for >>> upstream QEMU. In such a proposal, we intend to have further >>> integration. Ideally in way that "configure" can be given a >>> "--with-functional-[avocado-]tests" parameter of sorts, and a "make >>> [functional-]check" would seamlessly include them. >> >> I have a few thoughts. >> >> We use pytest/pexpect internally to kick off QEMU runs and monitor the >> output (no interaction with the QEMU source tree) and I think it is >> extremely useful. So I am all for using Python to test things and this >> looks really well done! >> > > Thanks for checking it out, and for the positive words. Now, sorry if > I'm missing some obvious information, but is this work of yours with > pytest/pexpect publicly available? I'd like to also take a look at > that, because it does look similar to the Avocado + aexpect approach > taken here.
Unfortunately it's not and it would take months for us to be able to make it available. > >> What I don't understand though is what this gives us compared to the >> existing QEMU test infrastructure? Besides being able to use Python >> and a better interface what are the main benefits? I think that is >> something worth documenting somewhere. >> > > We currently intend to *add* to the QEMU test infrastructure, not > replace it. Is there a benefit of integrating it into the tree then? It's always possible to have an out of tree testing framework. > > The benefits we envision are, besides hopefully easier and more capable > interfaces, to simply have more upstream tests. This means avoiding new > regressions and improving coverage. > >> Also, it looks like this will require images checked into git >> somewhere is that correct? Is there a good plan on how to handle that? >> > > It won't require images checked into git. Right now, tests use the > vmimage library: > > http://avocado-framework.readthedocs.io/en/57.0/api/utils/avocado.utils.html#avocado.utils.vmimage.get > > Which downloads (and caches) images from external sources. Ah! That's cool. Managing images is one of the challenges we have at the moment. Alistair > > Please let me know if you have more questions! > - Cleber. > >> Alistair >> >>> >>> Thanks! >>> >>> References >>> ========== >>> >>> [1] http://avocado-framework.github.io/ >>> [2] http://autotest.github.io/ >>> [3] https://github.com/autotest/virt-test >>> [4] https://github.com/avocado-framework/avocado-vt >>> [5] https://github.com/autotest/tp-qemu >>> [6] https://github.com/apahim/qemu >>> [7] https://github.com/apahim/qemu/tree/avocado_qemu >>> [8] https://github.com/apahim/qemu/tree/avocado_qemu_snapshot >>> [9] >>> https://github.com/apahim/qemu/blob/avocado_qemu/tests/avocado/test_info_memdev_host_nodes.py >>> [10] >>> https://github.com/apahim/qemu/blob/avocado_qemu/tests/avocado/test_ovmf_with_240_vcpus.py >>> [11] >>> https://github.com/apahim/qemu/blob/avocado_qemu/tests/avocado/README.rst >>> [12] http://avocado-framework.readthedocs.io/ >>> >>> -- >>> Cleber Rosa >>> [ Sr Software Engineer - Virtualization Team - Red Hat ] >>> [ Avocado Test Framework - avocado-framework.github.io ] >>> [ 7ABB 96EB 8B46 B94D 5E0F E9BB 657E 8D33 A5F2 09F3 ] >>> > > -- > Cleber Rosa > [ Sr Software Engineer - Virtualization Team - Red Hat ] > [ Avocado Test Framework - avocado-framework.github.io ] > [ 7ABB 96EB 8B46 B94D 5E0F E9BB 657E 8D33 A5F2 09F3 ]
