xref: /openbmc/qemu/docs/devel/qtest.rst (revision 8905770b)
1========================================
2QTest Device Emulation Testing Framework
3========================================
4
5.. toctree::
6
7   qgraph
8
9QTest is a device emulation testing framework.  It can be very useful to test
10device models; it could also control certain aspects of QEMU (such as virtual
11clock stepping), with a special purpose "qtest" protocol.  Refer to
12:ref:`qtest-protocol` for more details of the protocol.
13
14QTest cases can be executed with
15
16.. code::
17
18   make check-qtest
19
20The QTest library is implemented by ``tests/qtest/libqtest.c`` and the API is
21defined in ``tests/qtest/libqtest.h``.
22
23Consider adding a new QTest case when you are introducing a new virtual
24hardware, or extending one if you are adding functionalities to an existing
25virtual device.
26
27On top of libqtest, a higher level library, ``libqos``, was created to
28encapsulate common tasks of device drivers, such as memory management and
29communicating with system buses or devices. Many virtual device tests use
30libqos instead of directly calling into libqtest.
31Libqos also offers the Qgraph API to increase each test coverage and
32automate QEMU command line arguments and devices setup.
33Refer to :ref:`qgraph` for Qgraph explanation and API.
34
35Steps to add a new QTest case are:
36
371. Create a new source file for the test. (More than one file can be added as
38   necessary.) For example, ``tests/qtest/foo-test.c``.
39
402. Write the test code with the glib and libqtest/libqos API. See also existing
41   tests and the library headers for reference.
42
433. Register the new test in ``tests/qtest/meson.build``. Add the test
44   executable name to an appropriate ``qtests_*`` variable. There is
45   one variable per architecture, plus ``qtests_generic`` for tests
46   that can be run for all architectures.  For example::
47
48     qtests_generic = [
49       ...
50       'foo-test',
51       ...
52     ]
53
544. If the test has more than one source file or needs to be linked with any
55   dependency other than ``qemuutil`` and ``qos``, list them in the ``qtests``
56   dictionary.  For example a test that needs to use the ``QIO`` library
57   will have an entry like::
58
59     {
60       ...
61       'foo-test': [io],
62       ...
63     }
64
65Debugging a QTest failure is slightly harder than the unit test because the
66tests look up QEMU program names in the environment variables, such as
67``QTEST_QEMU_BINARY`` and ``QTEST_QEMU_IMG``, and also because it is not easy
68to attach gdb to the QEMU process spawned from the test. But manual invoking
69and using gdb on the test is still simple to do: find out the actual command
70from the output of
71
72.. code::
73
74  make check-qtest V=1
75
76which you can run manually.
77
78
79.. _qtest-protocol:
80
81QTest Protocol
82--------------
83
84.. kernel-doc:: softmmu/qtest.c
85   :doc: QTest Protocol
86
87
88libqtest API reference
89----------------------
90
91.. kernel-doc:: tests/qtest/libqos/libqtest.h
92