184
184
.. _testrepository: https://launchpad.net/testrepository
187
Babune continuous integration
188
-----------------------------
190
We have a Hudson continuous-integration system that automatically runs
191
tests across various platforms. In the future we plan to add more
192
combinations including testing plugins. See
193
<http://babune.ladeuil.net:24842/>. (Babune = Bazaar Buildbot Network.)
196
Running tests in parallel
197
-------------------------
199
Bazaar can use subunit to spawn multiple test processes. There is
200
slightly more chance you will hit ordering or timing-dependent bugs but
203
$ ./bzr selftest --parallel=fork
205
Note that you will need the Subunit library
206
<https://launchpad.net/subunit/> to use this, which is in
207
``python-subunit`` on Ubuntu.
210
Running tests from a ramdisk
211
----------------------------
213
The tests create and delete a lot of temporary files. In some cases you
214
can make the test suite run much faster by running it on a ramdisk. For
218
$ sudo mount -t tmpfs none /ram
219
$ TMPDIR=/ram ./bzr selftest ...
221
You could also change ``/tmp`` in ``/etc/fstab`` to have type ``tmpfs``,
222
if you don't mind possibly losing other files in there when the machine
223
restarts. Add this line (if there is none for ``/tmp`` already)::
225
none /tmp tmpfs defaults 0 0
227
With a 6-core machine and ``--parallel=fork`` using a tmpfs doubles the
228
test execution speed.
298
``bzrlib/tests/script.py`` allows users to write tests in a syntax very close to a shell session,
299
using a restricted and limited set of commands that should be enough to mimic
300
most of the behaviours.
343
``bzrlib/tests/script.py`` allows users to write tests in a syntax very
344
close to a shell session, using a restricted and limited set of commands
345
that should be enough to mimic most of the behaviours.
302
347
A script is a set of commands, each command is composed of:
322
367
The execution stops as soon as an expected output or an expected error is not
325
When no output is specified, any ouput from the command is accepted
326
and execution continue.
370
If output occurs and no output is expected, the execution stops and the
371
test fails. If unexpected output occurs on the standard error, then
372
execution stops and the test fails.
328
374
If an error occurs and no expected error is specified, the execution stops.
437
You can run files containing shell-like scripts with::
439
$ bzr test-script <script>
441
where ``<script>`` is the path to the file containing the shell-like script.
385
443
The actual use of ScriptRunner within a TestCase looks something like
388
def test_unshelve_keep(self):
391
sr.run_script(self, '''
393
$ bzr shelve --all -m Foo
396
$ bzr unshelve --keep
446
from bzrlib.tests import script
448
def test_unshelve_keep(self):
450
script.run_script(self, '''
452
$ bzr shelve -q --all -m Foo
455
$ bzr unshelve -q --keep
462
You can also test commands that read user interaction::
464
def test_confirm_action(self):
465
"""You can write tests that demonstrate user confirmation"""
466
commands.builtin_command_registry.register(cmd_test_confirm)
467
self.addCleanup(commands.builtin_command_registry.remove, 'test-confirm')
470
2>Really do it? [y/n]:
475
To avoid having to specify "-q" for all commands whose output is
476
irrelevant, the run_script() method may be passed the keyword argument
477
``null_output_matches_anything=True``. For example::
479
def test_ignoring_null_output(self):
482
$ bzr ci -m 'first revision' --unchanged
485
""", null_output_matches_anything=True)
404
488
Import tariff tests
405
489
-------------------
653
737
_test_needs_features = [features.apport]
740
Testing deprecated code
741
-----------------------
743
When code is deprecated, it is still supported for some length of time,
744
usually until the next major version. The ``applyDeprecated`` helper
745
wraps calls to deprecated code to verify that it is correctly issuing the
746
deprecation warning, and also prevents the warnings from being printed
749
Typically patches that apply the ``@deprecated_function`` decorator should
750
update the accompanying tests to use the ``applyDeprecated`` wrapper.
752
``applyDeprecated`` is defined in ``bzrlib.tests.TestCase``. See the API
753
docs for more details.
656
756
Testing exceptions and errors
657
757
-----------------------------
731
831
whether a test should be added for that particular implementation,
732
832
or for all implementations of the interface.
734
The multiplication of tests for different implementations is normally
735
accomplished by overriding the ``load_tests`` function used to load tests
736
from a module. This function typically loads all the tests, then applies
737
a TestProviderAdapter to them, which generates a longer suite containing
738
all the test variations.
740
834
See also `Per-implementation tests`_ (above).
837
Test scenarios and variations
838
-----------------------------
746
840
Some utilities are provided for generating variations of tests. This can
747
841
be used for per-implementation tests, or other cases where the same test
752
846
values to which the test should be applied. The test suite should then
753
847
also provide a list of scenarios in which to run the tests.
755
Typically ``multiply_tests_from_modules`` should be called from the test
756
module's ``load_tests`` function.
849
A single *scenario* is defined by a `(name, parameter_dict)` tuple. The
850
short string name is combined with the name of the test method to form the
851
test instance name. The parameter dict is merged into the instance's
856
load_tests = load_tests_apply_scenarios
858
class TestCheckout(TestCase):
860
scenarios = multiply_scenarios(
861
VaryByRepositoryFormat(),
865
The `load_tests` declaration or definition should be near the top of the
866
file so its effect can be seen.
774
884
A base TestCase that extends the Python standard library's
775
TestCase in several ways. It adds more assertion methods (e.g.
776
``assertContainsRe``), ``addCleanup``, and other features (see its API
777
docs for details). It also has a ``setUp`` that makes sure that
778
global state like registered hooks and loggers won't interfere with
779
your test. All tests should use this base class (whether directly or
885
TestCase in several ways. TestCase is build on
886
``testtools.TestCase``, which gives it support for more assertion
887
methods (e.g. ``assertContainsRe``), ``addCleanup``, and other
888
features (see its API docs for details). It also has a ``setUp`` that
889
makes sure that global state like registered hooks and loggers won't
890
interfere with your test. All tests should use this base class
891
(whether directly or via a subclass). Note that we are trying not to
892
add more assertions at this point, and instead to build up a library
893
of ``bzrlib.tests.matchers``.
782
895
TestCaseWithMemoryTransport
783
896
Extends TestCase and adds methods like ``get_transport``,
856
969
Please see bzrlib.treebuilder for more details.
972
Temporarily changing state
973
~~~~~~~~~~~~~~~~~~~~~~~~~~
975
If your test needs to temporarily mutate some global state, and you need
976
it restored at the end, you can say for example::
978
self.overrideAttr(osutils, '_cached_user_encoding', 'latin-1')
980
Temporarily changing environment variables
981
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
983
If yout test needs to temporarily change some environment variable value
984
(which generally means you want it restored at the end), you can use::
986
self.overrideEnv('BZR_ENV_VAR', 'new_value')
988
If you want to remove a variable from the environment, you should use the
989
special ``None`` value::
991
self.overrideEnv('PATH', None)
993
If you add a new feature which depends on a new environment variable, make
994
sure it behaves properly when this variable is not defined (if applicable) and
995
if you need to enforce a specific default value, check the
996
``TestCase._cleanEnvironment`` in ``bzrlib.tests.__init__.py`` which defines a
997
proper set of values for all tests.
1002
Our base ``TestCase`` class provides an ``addCleanup`` method, which
1003
should be used instead of ``tearDown``. All the cleanups are run when the
1004
test finishes, regardless of whether it passes or fails. If one cleanup
1005
fails, later cleanups are still run.
1007
(The same facility is available outside of tests through
1008
``bzrlib.cleanup``.)
1014
Generally we prefer automated testing but sometimes a manual test is the
1015
right thing, especially for performance tests that want to measure elapsed
1016
time rather than effort.
1018
Simulating slow networks
1019
------------------------
1021
To get realistically slow network performance for manually measuring
1022
performance, we can simulate 500ms latency (thus 1000ms round trips)::
1024
$ sudo tc qdisc add dev lo root netem delay 500ms
1026
Normal system behaviour is restored with ::
1028
$ sudo tc qdisc del dev lo root
1030
A more precise version that only filters traffic to port 4155 is::
1032
tc qdisc add dev lo root handle 1: prio
1033
tc qdisc add dev lo parent 1:3 handle 30: netem delay 500ms
1034
tc qdisc add dev lo parent 30:1 handle 40: prio
1035
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip dport 4155 0xffff flowid 1:3 handle 800::800
1036
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip sport 4155 0xffff flowid 1:3 handle 800::801
1038
and to remove this::
1040
tc filter del dev lo protocol ip parent 1: pref 3 u32
1041
tc qdisc del dev lo root handle 1:
1043
You can use similar code to add additional delay to a real network
1044
interface, perhaps only when talking to a particular server or pointing at
1045
a VM. For more information see <http://lartc.org/>.
859
1048
.. |--| unicode:: U+2014
1051
vim: ft=rst tw=74 ai et sw=4
added
removed
doc/developers/testing.txt
