6
6
The Importance of Testing
7
7
=========================
9
Reliability is a critical success factor for any Version Control System.
9
Reliability is a critical success factor for any version control system.
10
10
We want Bazaar to be highly reliable across multiple platforms while
11
11
evolving over time to meet the needs of its community.
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.
385
436
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
439
from bzrlib.tests import script
441
def test_unshelve_keep(self):
443
script.run_script(self, '''
445
$ bzr shelve --all -m Foo
448
$ bzr unshelve --keep
455
You can also test commands that read user interaction::
457
def test_confirm_action(self):
458
"""You can write tests that demonstrate user confirmation"""
459
commands.builtin_command_registry.register(cmd_test_confirm)
460
self.addCleanup(commands.builtin_command_registry.remove, 'test-confirm')
463
2>Really do it? [y/n]:
404
468
Import tariff tests
405
469
-------------------
420
484
dependencies and only needed for particular cases. If they're loaded in
421
485
other cases then bzr may break for people who don't have those modules.
423
`test_import_tarrif` allows us to check that removal of imports doesn't
487
`test_import_tariff` allows us to check that removal of imports doesn't
426
490
This is done by running the command in a subprocess with
653
717
_test_needs_features = [features.apport]
720
Testing deprecated code
721
-----------------------
723
When code is deprecated, it is still supported for some length of time,
724
usually until the next major version. The ``applyDeprecated`` helper
725
wraps calls to deprecated code to verify that it is correctly issuing the
726
deprecation warning, and also prevents the warnings from being printed
729
Typically patches that apply the ``@deprecated_function`` decorator should
730
update the accompanying tests to use the ``applyDeprecated`` wrapper.
732
``applyDeprecated`` is defined in ``bzrlib.tests.TestCase``. See the API
733
docs for more details.
656
736
Testing exceptions and errors
657
737
-----------------------------
859
939
Please see bzrlib.treebuilder for more details.
942
Temporarily changing state
943
~~~~~~~~~~~~~~~~~~~~~~~~~~
945
If your test needs to temporarily mutate some global state, and you need
946
it restored at the end, you can say for example::
948
self.overrideAttr(osutils, '_cached_user_encoding', 'latin-1')
953
Our base ``TestCase`` class provides an ``addCleanup`` method, which
954
should be used instead of ``tearDown``. All the cleanups are run when the
955
test finishes, regardless of whether it passes or fails. If one cleanup
956
fails, later cleanups are still run.
958
(The same facility is available outside of tests through
965
Generally we prefer automated testing but sometimes a manual test is the
966
right thing, especially for performance tests that want to measure elapsed
967
time rather than effort.
969
Simulating slow networks
970
------------------------
972
To get realistically slow network performance for manually measuring
973
performance, we can simulate 500ms latency (thus 1000ms round trips)::
975
$ sudo tc qdisc add dev lo root netem delay 500ms
977
Normal system behaviour is restored with ::
979
$ sudo tc qdisc del dev lo root
981
A more precise version that only filters traffic to port 4155 is::
983
tc qdisc add dev lo root handle 1: prio
984
tc qdisc add dev lo parent 1:3 handle 30: netem delay 500ms
985
tc qdisc add dev lo parent 30:1 handle 40: prio
986
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip dport 4155 0xffff flowid 1:3 handle 800::800
987
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip sport 4155 0xffff flowid 1:3 handle 800::801
991
tc filter del dev lo protocol ip parent 1: pref 3 u32
992
tc qdisc del dev lo root handle 1:
994
You can use similar code to add additional delay to a real network
995
interface, perhaps only when talking to a particular server or pointing at
996
a VM. For more information see <http://lartc.org/>.
862
999
.. |--| unicode:: U+2014
1002
vim: ft=rst tw=74 ai et sw=4
added
removed
doc/developers/testing.txt
