24
24
starting on the code itself. Check the test fails on the old code, then
25
25
add the feature or fix and check it passes.
27
By doing these things, the Breezy team gets increased confidence that
27
By doing these things, the Bazaar team gets increased confidence that
28
28
changes do what they claim to do, whether provided by the core team or
29
29
by community members. Equally importantly, we can be surer that changes
30
30
down the track do not break new features or bug fixes that you are
31
31
contributing today.
33
As of September 2009, Breezy ships with a test suite containing over
33
As of September 2009, Bazaar ships with a test suite containing over
34
34
23,000 tests and growing. We are proud of it and want to remain so. As
35
35
community members, we all benefit from it. Would you trust version control
36
on your project to a product *without* a test suite like Breezy has?
36
on your project to a product *without* a test suite like Bazaar has?
39
39
Running the Test Suite
40
40
======================
42
As of Breezy 2.1, you must have the testtools_ library installed to run
42
As of Bazaar 2.1, you must have the testtools_ library installed to run
45
45
.. _testtools: https://launchpad.net/testtools/
47
To test all of Breezy, just run::
51
With ``--verbose`` brz will print the name of every test as it is run.
47
To test all of Bazaar, just run::
51
With ``--verbose`` bzr will print the name of every test as it is run.
53
53
This should always pass, whether run from a source tree or an installed
54
copy of Breezy. Please investigate and/or report any failures.
54
copy of Bazaar. Please investigate and/or report any failures.
57
57
Running particular tests
58
58
------------------------
60
Currently, brz selftest is used to invoke tests.
60
Currently, bzr selftest is used to invoke tests.
61
61
You can provide a pattern argument to run a subset. For example,
62
62
to run just the blackbox tests, run::
64
./brz selftest -v blackbox
64
./bzr selftest -v blackbox
66
66
To skip a particular test (or set of tests), use the --exclude option
67
67
(shorthand -x) like so::
69
./brz selftest -v -x blackbox
69
./bzr selftest -v -x blackbox
71
71
To ensure that all tests are being run and succeeding, you can use the
72
72
--strict option which will fail if there are any missing features or known
73
73
failures, like so::
75
./brz selftest --strict
75
./bzr selftest --strict
77
77
To list tests without running them, use the --list-only option like so::
79
./brz selftest --list-only
79
./bzr selftest --list-only
81
81
This option can be combined with other selftest options (like -x) and
82
82
filter patterns to understand their effect.
107
107
Disabling plugins
108
108
-----------------
110
To test only the brz core, ignoring any plugins you may have installed,
110
To test only the bzr core, ignoring any plugins you may have installed,
113
./brz --no-plugins selftest
113
./bzr --no-plugins selftest
115
115
Disabling crash reporting
116
116
-------------------------
118
By default Breezy uses apport_ to report program crashes. In developing
119
Breezy it's normal and expected to have it crash from time to time, at
118
By default Bazaar uses apport_ to report program crashes. In developing
119
Bazaar it's normal and expected to have it crash from time to time, at
120
120
least because a test failed if for no other reason.
122
122
Therefore you should probably add ``debug_flags = no_apport`` to your
123
``breezy.conf`` file (in ``~/.config/breezy/`` on Unix), so that failures just
123
``bazaar.conf`` file (in ``~/.bazaar/`` on Unix), so that failures just
124
124
print a traceback rather than writing a crash file.
126
126
.. _apport: https://launchpad.net/apport/
184
184
.. _testrepository: https://launchpad.net/testrepository
187
Running tests in parallel
188
-------------------------
190
Breezy can use subunit to spawn multiple test processes. There is
191
slightly more chance you will hit ordering or timing-dependent bugs but
194
$ ./brz selftest --parallel=fork
196
Note that you will need the Subunit library
197
<https://launchpad.net/subunit/> to use this, which is in
198
``python-subunit`` on Ubuntu.
201
Running tests from a ramdisk
202
----------------------------
204
The tests create and delete a lot of temporary files. In some cases you
205
can make the test suite run much faster by running it on a ramdisk. For
209
$ sudo mount -t tmpfs none /ram
210
$ TMPDIR=/ram ./brz selftest ...
212
You could also change ``/tmp`` in ``/etc/fstab`` to have type ``tmpfs``,
213
if you don't mind possibly losing other files in there when the machine
214
restarts. Add this line (if there is none for ``/tmp`` already)::
216
none /tmp tmpfs defaults 0 0
218
With a 6-core machine and ``--parallel=fork`` using a tmpfs doubles the
219
test execution speed.
225
189
Normally you should add or update a test for all bug fixes or new features
229
193
Where should I put a new test?
230
194
------------------------------
232
breezy's tests are organised by the type of test. Most of the tests in
233
brz's test suite belong to one of these categories:
196
Bzrlib's tests are organised by the type of test. Most of the tests in
197
bzr's test suite belong to one of these categories:
236
200
- Blackbox (UI) tests
237
201
- Per-implementation tests
240
A quick description of these test types and where they belong in breezy's
204
A quick description of these test types and where they belong in bzrlib's
241
205
source follows. Not all tests fall neatly into one of these categories;
242
206
in those cases use your judgement.
266
230
option, then you should be writing a UI test. If you are both adding UI
267
231
functionality and library functionality, you will want to write tests for
268
232
both the UI and the core behaviours. We call UI tests 'blackbox' tests
269
and they belong in ``breezy/tests/blackbox/*.py``.
233
and they belong in ``bzrlib/tests/blackbox/*.py``.
271
235
When writing blackbox tests please honour the following conventions:
273
237
1. Place the tests for the command 'name' in
274
breezy/tests/blackbox/test_name.py. This makes it easy for developers
238
bzrlib/tests/blackbox/test_name.py. This makes it easy for developers
275
239
to locate the test script for a faulty command.
277
2. Use the 'self.run_brz("name")' utility function to invoke the command
278
rather than running brz in a subprocess or invoking the
241
2. Use the 'self.run_bzr("name")' utility function to invoke the command
242
rather than running bzr in a subprocess or invoking the
279
243
cmd_object.run() method directly. This is a lot faster than
280
244
subprocesses and generates the same logging output as running it in a
281
245
subprocess (which invoking the method directly does not).
283
3. Only test the one command in a single test script. Use the breezy
247
3. Only test the one command in a single test script. Use the bzrlib
284
248
library when setting up tests and when evaluating the side-effects of
285
249
the command. We do this so that the library api has continual pressure
286
250
on it to be as functional as the command line in a simple manner, and
300
264
against multiple implementations of an interface. For example,
301
265
``per_transport.py`` defines tests that all Transport implementations
302
266
(local filesystem, HTTP, and so on) must pass. They are found in
303
``breezy/tests/per_*/*.py``, and ``breezy/tests/per_*.py``.
267
``bzrlib/tests/per_*/*.py``, and ``bzrlib/tests/per_*.py``.
305
269
These are really a sub-category of unit tests, but an important one.
307
271
Along the same lines are tests for extension modules. We generally have
308
272
both a pure-python and a compiled implementation for each module. As such,
309
273
we want to run the same tests against both implementations. These can
310
generally be found in ``breezy/tests/*__*.py`` since extension modules are
274
generally be found in ``bzrlib/tests/*__*.py`` since extension modules are
311
275
usually prefixed with an underscore. Since there are only two
312
276
implementations, we have a helper function
313
``breezy.tests.permute_for_extension``, which can simplify the
277
``bzrlib.tests.permute_for_extension``, which can simplify the
314
278
``load_tests`` implementation.
320
284
We make selective use of doctests__. In general they should provide
321
285
*examples* within the API documentation which can incidentally be tested. We
322
286
don't try to test every important case using doctests |--| regular Python
323
tests are generally a better solution. That is, we just use doctests to make
324
our documentation testable, rather than as a way to make tests. Be aware that
325
doctests are not as well isolated as the unit tests, if you need more
326
isolation, you're likely want to write unit tests anyway if only to get a
327
better control of the test environment.
287
tests are generally a better solution. That is, we just use doctests to
288
make our documentation testable, rather than as a way to make tests.
329
Most of these are in ``breezy/doc/api``. More additions are welcome.
290
Most of these are in ``bzrlib/doc/api``. More additions are welcome.
331
292
__ http://docs.python.org/lib/module-doctest.html
333
There is an `assertDoctestExampleMatches` method in
334
`breezy.tests.TestCase` that allows you to match against doctest-style
335
string templates (including ``...`` to skip sections) from regular Python
342
``breezy/tests/script.py`` allows users to write tests in a syntax very
343
close to a shell session, using a restricted and limited set of commands
344
that should be enough to mimic most of the behaviours.
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.
346
302
A script is a set of commands, each command is composed of:
436
You can run files containing shell-like scripts with::
438
$ brz test-script <script>
440
where ``<script>`` is the path to the file containing the shell-like script.
442
385
The actual use of ScriptRunner within a TestCase looks something like
445
from breezy.tests import script
447
def test_unshelve_keep(self):
449
script.run_script(self, '''
451
$ brz shelve -q --all -m Foo
454
$ brz unshelve -q --keep
461
You can also test commands that read user interaction::
463
def test_confirm_action(self):
464
"""You can write tests that demonstrate user confirmation"""
465
commands.builtin_command_registry.register(cmd_test_confirm)
466
self.addCleanup(commands.builtin_command_registry.remove, 'test-confirm')
469
2>Really do it? [y/n]:
474
To avoid having to specify "-q" for all commands whose output is
475
irrelevant, the run_script() method may be passed the keyword argument
476
``null_output_matches_anything=True``. For example::
478
def test_ignoring_null_output(self):
481
$ brz ci -m 'first revision' --unchanged
484
""", null_output_matches_anything=True)
388
def test_unshelve_keep(self):
391
sr.run_script(self, '''
393
$ bzr shelve --all -m Foo
396
$ bzr unshelve --keep
487
404
Import tariff tests
488
405
-------------------
490
`breezy.tests.test_import_tariff` has some tests that measure how many
407
`bzrlib.tests.test_import_tariff` has some tests that measure how many
491
408
Python modules are loaded to run some representative commands.
493
410
We want to avoid loading code unnecessarily, for reasons including:
502
419
* Some optional modules such as `testtools` are meant to be soft
503
420
dependencies and only needed for particular cases. If they're loaded in
504
other cases then brz may break for people who don't have those modules.
421
other cases then bzr may break for people who don't have those modules.
506
`test_import_tariff` allows us to check that removal of imports doesn't
423
`test_import_tarrif` allows us to check that removal of imports doesn't
509
426
This is done by running the command in a subprocess with
510
``PYTHON_VERBOSE=1``. Starting a whole Python interpreter is pretty slow,
511
so we don't want exhaustive testing here, but just enough to guard against
512
distinct fixed problems.
427
``--profile-imports``. Starting a whole Python interpreter is pretty
428
slow, so we don't want exhaustive testing here, but just enough to guard
429
against distinct fixed problems.
514
431
Assertions about precisely what is loaded tend to be brittle so we instead
515
432
make assertions that particular things aren't loaded.
517
434
Unless selftest is run with ``--no-plugins``, modules will be loaded in
518
435
the usual way and checks made on what they cause to be loaded. This is
519
probably worth checking into, because many brz users have at least some
436
probably worth checking into, because many bzr users have at least some
520
437
plugins installed (and they're included in binary installers).
522
439
In theory, plugins might have a good reason to load almost anything:
523
440
someone might write a plugin that opens a network connection or pops up a
524
gui window every time you run 'brz status'. However, it's more likely
441
gui window every time you run 'bzr status'. However, it's more likely
525
442
that the code to do these things is just being loaded accidentally. We
526
443
might eventually need to have a way to make exceptions for particular
723
640
A helper for handling running tests based on whether a python
724
641
module is available. This can handle 3rd-party dependencies (is
725
642
``paramiko`` available?) as well as stdlib (``termios``) or
726
extension modules (``breezy._groupcompress_pyx``). You create a
643
extension modules (``bzrlib._groupcompress_pyx``). You create a
727
644
new feature instance with::
729
# in breezy/tests/features.py
646
# in bzrlib/tests/features.py
730
647
apport = tests.ModuleAvailableFeature('apport')
733
# then in breezy/tests/test_apport.py
650
# then in bzrlib/tests/test_apport.py
734
651
class TestApportReporting(TestCaseInTempDir):
736
653
_test_needs_features = [features.apport]
740
-----------------------
742
Translations are disabled by default in tests. If you want to test
743
that code is translated you can use the ``ZzzTranslations`` class from
746
self.overrideAttr(i18n, '_translations', ZzzTranslations())
748
And check the output strings look like ``u"zz\xe5{{output}}"``.
750
To test the gettext setup and usage you override i18n.installed back
751
to self.i18nInstalled and _translations to None, see
752
test_i18n.TestInstall.
755
Testing deprecated code
756
-----------------------
758
When code is deprecated, it is still supported for some length of time,
759
usually until the next major version. The ``applyDeprecated`` helper
760
wraps calls to deprecated code to verify that it is correctly issuing the
761
deprecation warning, and also prevents the warnings from being printed
764
Typically patches that apply the ``@deprecated_function`` decorator should
765
update the accompanying tests to use the ``applyDeprecated`` wrapper.
767
``applyDeprecated`` is defined in ``breezy.tests.TestCase``. See the API
768
docs for more details.
771
656
Testing exceptions and errors
772
657
-----------------------------
892
767
TestCase and its subclasses
893
768
~~~~~~~~~~~~~~~~~~~~~~~~~~~
895
The ``breezy.tests`` module defines many TestCase classes to help you
770
The ``bzrlib.tests`` module defines many TestCase classes to help you
896
771
write your tests.
899
774
A base TestCase that extends the Python standard library's
900
TestCase in several ways. TestCase is build on
901
``testtools.TestCase``, which gives it support for more assertion
902
methods (e.g. ``assertContainsRe``), ``addCleanup``, and other
903
features (see its API docs for details). It also has a ``setUp`` that
904
makes sure that global state like registered hooks and loggers won't
905
interfere with your test. All tests should use this base class
906
(whether directly or via a subclass). Note that we are trying not to
907
add more assertions at this point, and instead to build up a library
908
of ``breezy.tests.matchers``.
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
910
782
TestCaseWithMemoryTransport
911
783
Extends TestCase and adds methods like ``get_transport``,
981
853
method of ``TestCaseWithMemoryTransport``) or ``make_branch_and_tree`` (a
982
854
method of ``TestCaseWithTransport``).
984
Please see breezy.treebuilder for more details.
989
PreviewTrees are based on TreeTransforms. This means they can represent
990
virtually any state that a WorkingTree can have, including unversioned files.
991
They can be used to test the output of anything that produces TreeTransforms,
992
such as merge algorithms and revert. They can also be used to test anything
993
that takes arbitrary Trees as its input.
997
# Get an empty tree to base the transform on.
998
b = self.make_branch('.')
999
empty_tree = b.repository.revision_tree(_mod_revision.NULL_REVISION)
1000
tt = TransformPreview(empty_tree)
1001
self.addCleanup(tt.finalize)
1002
# Empty trees don't have a root, so add it first.
1003
root = tt.new_directory('', ROOT_PARENT, 'tree-root')
1004
# Set the contents of a file.
1005
tt.new_file('new-file', root, 'contents', 'file-id')
1006
preview = tt.get_preview_tree()
1007
# Test the contents.
1008
self.assertEqual('contents', preview.get_file_text('file-id'))
1010
PreviewTrees can stack, with each tree falling back to the previous::
1012
tt2 = TransformPreview(preview)
1013
self.addCleanup(tt2.finalize)
1014
tt2.new_file('new-file2', tt2.root, 'contents2', 'file-id2')
1015
preview2 = tt2.get_preview_tree()
1016
self.assertEqual('contents', preview2.get_file_text('file-id'))
1017
self.assertEqual('contents2', preview2.get_file_text('file-id2'))
1020
Temporarily changing state
1021
~~~~~~~~~~~~~~~~~~~~~~~~~~
1023
If your test needs to temporarily mutate some global state, and you need
1024
it restored at the end, you can say for example::
1026
self.overrideAttr(osutils, '_cached_user_encoding', 'latin-1')
1028
This should be used with discretion; sometimes it's better to make the
1029
underlying code more testable so that you don't need to rely on monkey
1033
Observing calls to a function
1034
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1036
Sometimes it's useful to observe how a function is called, typically when
1037
calling it has side effects but the side effects are not easy to observe
1038
from a test case. For instance the function may be expensive and we want
1039
to assert it is not called too many times, or it has effects on the
1040
machine that are safe to run during a test but not easy to measure. In
1041
these cases, you can use `recordCalls` which will monkey-patch in a
1042
wrapper that records when the function is called.
1045
Temporarily changing environment variables
1046
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1048
If yout test needs to temporarily change some environment variable value
1049
(which generally means you want it restored at the end), you can use::
1051
self.overrideEnv('brz_ENV_VAR', 'new_value')
1053
If you want to remove a variable from the environment, you should use the
1054
special ``None`` value::
1056
self.overrideEnv('PATH', None)
1058
If you add a new feature which depends on a new environment variable, make
1059
sure it behaves properly when this variable is not defined (if applicable) and
1060
if you need to enforce a specific default value, check the
1061
``TestCase._cleanEnvironment`` in ``breezy.tests.__init__.py`` which defines a
1062
proper set of values for all tests.
1067
Our base ``TestCase`` class provides an ``addCleanup`` method, which
1068
should be used instead of ``tearDown``. All the cleanups are run when the
1069
test finishes, regardless of whether it passes or fails. If one cleanup
1070
fails, later cleanups are still run.
1072
(The same facility is available outside of tests through
1073
``breezy.cleanup``.)
1079
Generally we prefer automated testing but sometimes a manual test is the
1080
right thing, especially for performance tests that want to measure elapsed
1081
time rather than effort.
1083
Simulating slow networks
1084
------------------------
1086
To get realistically slow network performance for manually measuring
1087
performance, we can simulate 500ms latency (thus 1000ms round trips)::
1089
$ sudo tc qdisc add dev lo root netem delay 500ms
1091
Normal system behaviour is restored with ::
1093
$ sudo tc qdisc del dev lo root
1095
A more precise version that only filters traffic to port 4155 is::
1097
tc qdisc add dev lo root handle 1: prio
1098
tc qdisc add dev lo parent 1:3 handle 30: netem delay 500ms
1099
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip dport 4155 0xffff flowid 1:3
1100
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip sport 4155 0xffff flowid 1:3
1102
and to remove this::
1104
tc filter del dev lo protocol ip parent 1: pref 3 u32
1105
tc qdisc del dev lo root handle 1:
1107
You can use similar code to add additional delay to a real network
1108
interface, perhaps only when talking to a particular server or pointing at
1109
a VM. For more information see <http://lartc.org/>.
856
Please see bzrlib.treebuilder for more details.
1112
859
.. |--| unicode:: U+2014
1115
vim: ft=rst tw=74 ai et sw=4
added
removed
doc/developers/testing.txt
