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
774
838
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
839
TestCase in several ways. TestCase is build on
840
``testtools.TestCase``, which gives it support for more assertion
841
methods (e.g. ``assertContainsRe``), ``addCleanup``, and other
842
features (see its API docs for details). It also has a ``setUp`` that
843
makes sure that global state like registered hooks and loggers won't
844
interfere with your test. All tests should use this base class
845
(whether directly or via a subclass). Note that we are trying not to
846
add more assertions at this point, and instead to build up a library
847
of ``bzrlib.tests.matchers``.
782
849
TestCaseWithMemoryTransport
783
850
Extends TestCase and adds methods like ``get_transport``,
856
923
Please see bzrlib.treebuilder for more details.
926
Temporarily changing state
927
~~~~~~~~~~~~~~~~~~~~~~~~~~
929
If your test needs to temporarily mutate some global state, and you need
930
it restored at the end, you can say for example::
932
self.overrideAttr(osutils, '_cached_user_encoding', 'latin-1')
937
Our base ``TestCase`` class provides an ``addCleanup`` method, which
938
should be used instead of ``tearDown``. All the cleanups are run when the
939
test finishes, regardless of whether it passes or fails. If one cleanup
940
fails, later cleanups are still run.
942
(The same facility is available outside of tests through
949
Generally we prefer automated testing but sometimes a manual test is the
950
right thing, especially for performance tests that want to measure elapsed
951
time rather than effort.
953
Simulating slow networks
954
------------------------
956
To get realistically slow network performance for manually measuring
957
performance, we can simulate 500ms latency (thus 1000ms round trips)::
959
$ sudo tc qdisc add dev lo root netem delay 500ms
961
Normal system behaviour is restored with ::
963
$ sudo tc qdisc del dev lo root
965
A more precise version that only filters traffic to port 4155 is::
967
tc qdisc add dev lo root handle 1: prio
968
tc qdisc add dev lo parent 1:3 handle 30: netem delay 500ms
969
tc qdisc add dev lo parent 30:1 handle 40: prio
970
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip dport 4155 0xffff flowid 1:3 handle 800::800
971
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip sport 4155 0xffff flowid 1:3 handle 800::801
975
tc filter del dev lo protocol ip parent 1: pref 3 u32
976
tc qdisc del dev lo root handle 1:
978
You can use similar code to add additional delay to a real network
979
interface, perhaps only when talking to a particular server or pointing at
980
a VM. For more information see <http://lartc.org/>.
859
983
.. |--| unicode:: U+2014
986
vim: ft=rst tw=74 ai et sw=4
added
removed
doc/developers/testing.txt
