xref: /openbmc/qemu/docs/devel/qtest.rst (revision fc8c745d)
1========================================
2QTest Device Emulation Testing Framework
3========================================
4
5.. toctree::
6   :hidden:
7
8   qgraph
9
10QTest is a device emulation testing framework.  It can be very useful to test
11device models; it could also control certain aspects of QEMU (such as virtual
12clock stepping), with a special purpose "qtest" protocol.  Refer to
13:ref:`qtest-protocol` for more details of the protocol.
14
15QTest cases can be executed with
16
17.. code::
18
19   make check-qtest
20
21The QTest library is implemented by ``tests/qtest/libqtest.c`` and the API is
22defined in ``tests/qtest/libqtest.h``.
23
24Consider adding a new QTest case when you are introducing a new virtual
25hardware, or extending one if you are adding functionalities to an existing
26virtual device.
27
28On top of libqtest, a higher level library, ``libqos``, was created to
29encapsulate common tasks of device drivers, such as memory management and
30communicating with system buses or devices. Many virtual device tests use
31libqos instead of directly calling into libqtest.
32Libqos also offers the Qgraph API to increase each test coverage and
33automate QEMU command line arguments and devices setup.
34Refer to :ref:`qgraph` for Qgraph explanation and API.
35
36Steps to add a new QTest case are:
37
381. Create a new source file for the test. (More than one file can be added as
39   necessary.) For example, ``tests/qtest/foo-test.c``.
40
412. Write the test code with the glib and libqtest/libqos API. See also existing
42   tests and the library headers for reference.
43
443. Register the new test in ``tests/qtest/meson.build``. Add the test
45   executable name to an appropriate ``qtests_*`` variable. There is
46   one variable per architecture, plus ``qtests_generic`` for tests
47   that can be run for all architectures.  For example::
48
49     qtests_generic = [
50       ...
51       'foo-test',
52       ...
53     ]
54
554. If the test has more than one source file or needs to be linked with any
56   dependency other than ``qemuutil`` and ``qos``, list them in the ``qtests``
57   dictionary.  For example a test that needs to use the ``QIO`` library
58   will have an entry like::
59
60     {
61       ...
62       'foo-test': [io],
63       ...
64     }
65
66Debugging a QTest failure is slightly harder than the unit test because the
67tests look up QEMU program names in the environment variables, such as
68``QTEST_QEMU_BINARY`` and ``QTEST_QEMU_IMG``, and also because it is not easy
69to attach gdb to the QEMU process spawned from the test. But manual invoking
70and using gdb on the test is still simple to do: find out the actual command
71from the output of
72
73.. code::
74
75  make check-qtest V=1
76
77which you can run manually.
78
79
80.. _qtest-protocol:
81
82QTest Protocol
83--------------
84
85.. kernel-doc:: softmmu/qtest.c
86   :doc: QTest Protocol
87
88
89libqtest API reference
90----------------------
91
92.. kernel-doc:: tests/qtest/libqos/libqtest.h
93