On 01/28/2018 09:31 PM, Fam Zheng wrote: > To make our efforts on QEMU testing easier to consume by contributors, > let's add a document. For example, Patchew reports build errors on > patches that should be relativly easy to reproduce with a few steps, and
s/relativly/relatively/ > it is much nicer if there is such a documentation that it can refer to. > > This focues on how to run existing tests and how to write new test s/focues/focuses/ > cases, without going into the frameworks themselves. > > Signed-off-by: Fam Zheng <f...@redhat.com> > > --- > I'll try not to repeat comments made by others... > +This document describes the testing infrastructure in QEMU. > + > +"Make check" testings > +===================== s/testings/tests/, or 'Testing with "make check"' > + > +The "make check" testing family includes most of the C based tests in QEMU. > For > +a quick help, run ``make check-help`` from the source tree. > + > +The usual way to run these tests is: > + > +.. code:: > + > + make check > + > +which includes QAPI schema tests, unit tests, and QTests. Different sub-types > +of "make check" testings will be explained below. s/testings/tests/ > + > +Before running tests, it is best to build QEMU programs first. Some tests > +expect the executables to exist and will fail with obscure messages if cannot > +find them. Should we fix 'make check' to depend on 'make all', so that we don't have to require this? > + > +Unit tests > +---------- > + > +Unit tests, which can be invoked with ``make check-unit``, are simple C tests > +that typically link to individual QEMU objects and exercise them by calling > +into the modules. > + > +If you are writing new code in QEMU, consider adding a unit test, especially > +for utility modules that are relatively stateless or have few dependencies. > To > +add a new unit test: > + > +1. Create a new source file. For example, ``tests/test-foo.c``. > + > +2. Write the test. Normally you would include the headers file which exports > + the module API, then verify the interface behaves as expected from your > + test. The test code should be organized with the glib testing framework. > + Copy and modify an existing test is usually a good idea. > + > +3. Add the test to ``tests/Makefile.include``. First, name the unit test > + program and add it to ``$(check-unit-y)``; then add a rule to build the > + executable. Optionally, you can add a magical variable to support > ``gcov``. > + For example: > + > +.. code:: > + > + check-unit-y += tests/test-foo$(EXESUF) > + tests/test-foo$(EXESUF): tests/test-foo.o $(test-util-obj-y) > + ... > + gcov-files-test-foo-y = util/foo.c Is it worth documenting that you can often run 'gdb ./test-foo' after the fact for a failing test? (Most unit tests don't require any magic environment variables to be set) > + > +QTest > +----- > + > +QTest is a testing framework that simplifies starting QEMU and interacting > with > +the virtual machine just like a guest kernel does. It can be very useful to > +test hardware emulation, for example; it could also control certain aspects > of > +QEMU (such as virtual clock stepping), with a specially purposed "qtest" > +protocol. Refer to the documentation in ``qtest.c`` file for more details of > +the protocol. > + > +QTest cases can be executed with > + > +.. code:: > + > + make check-qtest > + > +The QTest library is implemented by ``tests/libqtest.c`` and the API is > defined > +in ``tests/libqtest.h``. > + > +Consider adding a new QTest case when you are introducing a new virtual > +hardware, or extending one if you are adding functionalities to an existing > +virtual device. > + > +On top of libqtest, a higher level library, ``libqos``, was created to > +encapsulate common tasks of device drivers, such as memory management and > +communicating with system buses or devices. Many virtual device tests use > +libqos instead of directly calling into libqos. > + > +Steps to add a new QTest case are: > + > +1. Create a new source file for the test. (More than one file can be added as > + necessary.) For example, ``tests/test-foo-device.c``. 2. Write the test > + code with the glib and libqtest/libqos API. See also existing tests and > the > + library headers for reference. > + > +3. Register the new test in ``tests/Makefile.include``. Add the test > executable > + name to an appropriate ``check-qtest-*-y`` variable. For example: > + > + ``check-qtest-generic-y = tests/test-foo-device$(EXESUF)`` > + > +4. Add object dependencies of the executable in the Makefile, including the > + test source file(s) and other interesting objects. For example: > + > + ``tests/test-foo-device$(EXESUF): tests/test-foo-device.o > $(libqos-obj-y)`` Is it worth documenting that 'make check-qtest' runs EVERY test unless you define magic environment variables; and if it fails, running 'make check-qtest V=1' can help identify which test failed? Here, running a mere 'gdb foo-device-test' is prone to fail (because it is missing magic environment variables); it's possible to run individual tests under gdb but it requires more effort (among other things, the V=1 helps you learn what environment variables to set). > + > +Docker based testing > +==================== 'Docker based tests' or 'Testing with docker' > + > +Introduction > +------------ > + > +Docker testing framework in QEMU utilizes the public Docker images to build > and s/^Docker/The Docker/ s/the public/public/ > +test QEMU in predefined and widely accessible Linux environments. This makes > +it possible to expand the test coverage across distros, toolchain flavors and > +library versions. > + -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
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