136
97
This can provide useful logging to help debug test failures when used
137
98
with e.g. ``bzr -Dhpss selftest -E=allow_debug``
139
Note that this will probably cause some tests to fail, because they
140
don't expect to run with any debug flags on.
146
Bazaar can optionally produce output in the machine-readable subunit_
147
format, so that test output can be post-processed by various tools. To
148
generate a subunit test stream::
150
$ ./bzr selftest --subunit
152
Processing such a stream can be done using a variety of tools including:
154
* The builtin ``subunit2pyunit``, ``subunit-filter``, ``subunit-ls``,
155
``subunit2junitxml`` from the subunit project.
157
* tribunal_, a GUI for showing test results.
159
* testrepository_, a tool for gathering and managing test runs.
161
.. _subunit: https://launchpad.net/subunit/
162
.. _tribunal: https://launchpad.net/tribunal/
168
Bazaar ships with a config file for testrepository_. This can be very
169
useful for keeping track of failing tests and doing general workflow
170
support. To run tests using testrepository::
174
To run only failing tests::
176
$ testr run --failing
178
To run only some tests, without plugins::
180
$ test run test_selftest -- --no-plugins
182
See the testrepository documentation for more details.
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.
234
Normally you should add or update a test for all bug fixes or new features
238
104
Where should I put a new test?
239
105
------------------------------
329
195
We make selective use of doctests__. In general they should provide
330
196
*examples* within the API documentation which can incidentally be tested. We
331
197
don't try to test every important case using doctests |--| regular Python
332
tests are generally a better solution. That is, we just use doctests to make
333
our documentation testable, rather than as a way to make tests. Be aware that
334
doctests are not as well isolated as the unit tests, if you need more
335
isolation, you're likely want to write unit tests anyway if only to get a
336
better control of the test environment.
198
tests are generally a better solution. That is, we just use doctests to
199
make our documentation testable, rather than as a way to make tests.
338
201
Most of these are in ``bzrlib/doc/api``. More additions are welcome.
340
203
__ http://docs.python.org/lib/module-doctest.html
342
There is an `assertDoctestExampleMatches` method in
343
`bzrlib.tests.TestCase` that allows you to match against doctest-style
344
string templates (including ``...`` to skip sections) from regular Python
351
``bzrlib/tests/script.py`` allows users to write tests in a syntax very
352
close to a shell session, using a restricted and limited set of commands
353
that should be enough to mimic most of the behaviours.
209
``bzrlib/tests/script.py`` allows users to write tests in a syntax very close to a shell session,
210
using a restricted and limited set of commands that should be enough to mimic
211
most of the behaviours.
355
213
A script is a set of commands, each command is composed of:
445
You can run files containing shell-like scripts with::
447
$ bzr test-script <script>
449
where ``<script>`` is the path to the file containing the shell-like script.
451
296
The actual use of ScriptRunner within a TestCase looks something like
454
from bzrlib.tests import script
456
def test_unshelve_keep(self):
458
script.run_script(self, '''
460
$ bzr shelve -q --all -m Foo
463
$ bzr unshelve -q --keep
470
You can also test commands that read user interaction::
472
def test_confirm_action(self):
473
"""You can write tests that demonstrate user confirmation"""
474
commands.builtin_command_registry.register(cmd_test_confirm)
475
self.addCleanup(commands.builtin_command_registry.remove, 'test-confirm')
478
2>Really do it? [y/n]:
483
To avoid having to specify "-q" for all commands whose output is
484
irrelevant, the run_script() method may be passed the keyword argument
485
``null_output_matches_anything=True``. For example::
487
def test_ignoring_null_output(self):
490
$ bzr ci -m 'first revision' --unchanged
493
""", null_output_matches_anything=True)
499
`bzrlib.tests.test_import_tariff` has some tests that measure how many
500
Python modules are loaded to run some representative commands.
502
We want to avoid loading code unnecessarily, for reasons including:
504
* Python modules are interpreted when they're loaded, either to define
505
classes or modules or perhaps to initialize some structures.
507
* With a cold cache we may incur blocking real disk IO for each module.
509
* Some modules depend on many others.
511
* Some optional modules such as `testtools` are meant to be soft
512
dependencies and only needed for particular cases. If they're loaded in
513
other cases then bzr may break for people who don't have those modules.
515
`test_import_tariff` allows us to check that removal of imports doesn't
518
This is done by running the command in a subprocess with
519
``PYTHON_VERBOSE=1``. Starting a whole Python interpreter is pretty slow,
520
so we don't want exhaustive testing here, but just enough to guard against
521
distinct fixed problems.
523
Assertions about precisely what is loaded tend to be brittle so we instead
524
make assertions that particular things aren't loaded.
526
Unless selftest is run with ``--no-plugins``, modules will be loaded in
527
the usual way and checks made on what they cause to be loaded. This is
528
probably worth checking into, because many bzr users have at least some
529
plugins installed (and they're included in binary installers).
531
In theory, plugins might have a good reason to load almost anything:
532
someone might write a plugin that opens a network connection or pops up a
533
gui window every time you run 'bzr status'. However, it's more likely
534
that the code to do these things is just being loaded accidentally. We
535
might eventually need to have a way to make exceptions for particular
538
Some things to check:
540
* non-GUI commands shouldn't load GUI libraries
542
* operations on bzr native formats sholudn't load foreign branch libraries
544
* network code shouldn't be loaded for purely local operations
546
* particularly expensive Python built-in modules shouldn't be loaded
547
unless there is a good reason
550
Testing locking behaviour
551
-------------------------
553
In order to test the locking behaviour of commands, it is possible to install
554
a hook that is called when a write lock is: acquired, released or broken.
555
(Read locks also exist, they cannot be discovered in this way.)
557
A hook can be installed by calling bzrlib.lock.Lock.hooks.install_named_hook.
558
The three valid hooks are: `lock_acquired`, `lock_released` and `lock_broken`.
565
lock.Lock.hooks.install_named_hook('lock_acquired',
566
locks_acquired.append, None)
567
lock.Lock.hooks.install_named_hook('lock_released',
568
locks_released.append, None)
570
`locks_acquired` will now receive a LockResult instance for all locks acquired
571
since the time the hook is installed.
573
The last part of the `lock_url` allows you to identify the type of object that is locked.
575
- BzrDir: `/branch-lock`
576
- Working tree: `/checkout/lock`
577
- Branch: `/branch/lock`
578
- Repository: `/repository/lock`
580
To test if a lock is a write lock on a working tree, one can do the following::
582
self.assertEndsWith(locks_acquired[0].lock_url, "/checkout/lock")
584
See bzrlib/tests/commands/test_revert.py for an example of how to use this for
299
def test_unshelve_keep(self):
302
sr.run_script(self, '''
304
$ bzr shelve --all -m Foo
307
$ bzr unshelve --keep
730
465
SymlinkFeature = _SymlinkFeature()
732
A helper for handling running tests based on whether a python
733
module is available. This can handle 3rd-party dependencies (is
734
``paramiko`` available?) as well as stdlib (``termios``) or
735
extension modules (``bzrlib._groupcompress_pyx``). You create a
736
new feature instance with::
738
# in bzrlib/tests/features.py
739
apport = tests.ModuleAvailableFeature('apport')
742
# then in bzrlib/tests/test_apport.py
743
class TestApportReporting(TestCaseInTempDir):
745
_test_needs_features = [features.apport]
748
Testing deprecated code
749
-----------------------
751
When code is deprecated, it is still supported for some length of time,
752
usually until the next major version. The ``applyDeprecated`` helper
753
wraps calls to deprecated code to verify that it is correctly issuing the
754
deprecation warning, and also prevents the warnings from being printed
757
Typically patches that apply the ``@deprecated_function`` decorator should
758
update the accompanying tests to use the ``applyDeprecated`` wrapper.
760
``applyDeprecated`` is defined in ``bzrlib.tests.TestCase``. See the API
761
docs for more details.
764
468
Testing exceptions and errors
765
469
-----------------------------
892
586
A base TestCase that extends the Python standard library's
893
TestCase in several ways. TestCase is build on
894
``testtools.TestCase``, which gives it support for more assertion
895
methods (e.g. ``assertContainsRe``), ``addCleanup``, and other
896
features (see its API docs for details). It also has a ``setUp`` that
897
makes sure that global state like registered hooks and loggers won't
898
interfere with your test. All tests should use this base class
899
(whether directly or via a subclass). Note that we are trying not to
900
add more assertions at this point, and instead to build up a library
901
of ``bzrlib.tests.matchers``.
587
TestCase in several ways. It adds more assertion methods (e.g.
588
``assertContainsRe``), ``addCleanup``, and other features (see its API
589
docs for details). It also has a ``setUp`` that makes sure that
590
global state like registered hooks and loggers won't interfere with
591
your test. All tests should use this base class (whether directly or
903
594
TestCaseWithMemoryTransport
904
595
Extends TestCase and adds methods like ``get_transport``,
977
668
Please see bzrlib.treebuilder for more details.
982
PreviewTrees are based on TreeTransforms. This means they can represent
983
virtually any state that a WorkingTree can have, including unversioned files.
984
They can be used to test the output of anything that produces TreeTransforms,
985
such as merge algorithms and revert. They can also be used to test anything
986
that takes arbitrary Trees as its input.
990
# Get an empty tree to base the transform on.
991
b = self.make_branch('.')
992
empty_tree = b.repository.revision_tree(_mod_revision.NULL_REVISION)
993
tt = TransformPreview(empty_tree)
994
self.addCleanup(tt.finalize)
995
# Empty trees don't have a root, so add it first.
996
root = tt.new_directory('', ROOT_PARENT, 'tree-root')
997
# Set the contents of a file.
998
tt.new_file('new-file', root, 'contents', 'file-id')
999
preview = tt.get_preview_tree()
1000
# Test the contents.
1001
self.assertEqual('contents', preview.get_file_text('file-id'))
1003
PreviewTrees can stack, with each tree falling back to the previous::
1005
tt2 = TransformPreview(preview)
1006
self.addCleanup(tt2.finalize)
1007
tt2.new_file('new-file2', tt2.root, 'contents2', 'file-id2')
1008
preview2 = tt2.get_preview_tree()
1009
self.assertEqual('contents', preview2.get_file_text('file-id'))
1010
self.assertEqual('contents2', preview2.get_file_text('file-id2'))
1013
Temporarily changing state
1014
~~~~~~~~~~~~~~~~~~~~~~~~~~
1016
If your test needs to temporarily mutate some global state, and you need
1017
it restored at the end, you can say for example::
1019
self.overrideAttr(osutils, '_cached_user_encoding', 'latin-1')
1021
This should be used with discretion; sometimes it's better to make the
1022
underlying code more testable so that you don't need to rely on monkey
1026
Observing calls to a function
1027
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1029
Sometimes it's useful to observe how a function is called, typically when
1030
calling it has side effects but the side effects are not easy to observe
1031
from a test case. For instance the function may be expensive and we want
1032
to assert it is not called too many times, or it has effects on the
1033
machine that are safe to run during a test but not easy to measure. In
1034
these cases, you can use `recordCalls` which will monkey-patch in a
1035
wrapper that records when the function is called.
1038
Temporarily changing environment variables
1039
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1041
If yout test needs to temporarily change some environment variable value
1042
(which generally means you want it restored at the end), you can use::
1044
self.overrideEnv('BZR_ENV_VAR', 'new_value')
1046
If you want to remove a variable from the environment, you should use the
1047
special ``None`` value::
1049
self.overrideEnv('PATH', None)
1051
If you add a new feature which depends on a new environment variable, make
1052
sure it behaves properly when this variable is not defined (if applicable) and
1053
if you need to enforce a specific default value, check the
1054
``TestCase._cleanEnvironment`` in ``bzrlib.tests.__init__.py`` which defines a
1055
proper set of values for all tests.
1060
Our base ``TestCase`` class provides an ``addCleanup`` method, which
1061
should be used instead of ``tearDown``. All the cleanups are run when the
1062
test finishes, regardless of whether it passes or fails. If one cleanup
1063
fails, later cleanups are still run.
1065
(The same facility is available outside of tests through
1066
``bzrlib.cleanup``.)
1072
Generally we prefer automated testing but sometimes a manual test is the
1073
right thing, especially for performance tests that want to measure elapsed
1074
time rather than effort.
1076
Simulating slow networks
1077
------------------------
1079
To get realistically slow network performance for manually measuring
1080
performance, we can simulate 500ms latency (thus 1000ms round trips)::
1082
$ sudo tc qdisc add dev lo root netem delay 500ms
1084
Normal system behaviour is restored with ::
1086
$ sudo tc qdisc del dev lo root
1088
A more precise version that only filters traffic to port 4155 is::
1090
tc qdisc add dev lo root handle 1: prio
1091
tc qdisc add dev lo parent 1:3 handle 30: netem delay 500ms
1092
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip dport 4155 0xffff flowid 1:3
1093
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip sport 4155 0xffff flowid 1:3
1095
and to remove this::
1097
tc filter del dev lo protocol ip parent 1: pref 3 u32
1098
tc qdisc del dev lo root handle 1:
1100
You can use similar code to add additional delay to a real network
1101
interface, perhaps only when talking to a particular server or pointing at
1102
a VM. For more information see <http://lartc.org/>.
1105
671
.. |--| unicode:: U+2014
1108
vim: ft=rst tw=74 ai et sw=4
added
removed
doc/developers/testing.txt
