329
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We make selective use of doctests__. In general they should provide
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*examples* within the API documentation which can incidentally be tested. We
331
331
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
333
make our documentation testable, rather than as a way to make tests.
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.
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Most of these are in ``bzrlib/doc/api``. More additions are welcome.
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__ http://docs.python.org/lib/module-doctest.html
342
There is an `assertDoctestExampleMatches` method in
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`bzrlib.tests.TestCase` that allows you to match against doctest-style
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string templates (including ``...`` to skip sections) from regular Python
343
``bzrlib/tests/script.py`` allows users to write tests in a syntax very close to a shell session,
344
using a restricted and limited set of commands that should be enough to mimic
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most of the behaviours.
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``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
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that should be enough to mimic most of the behaviours.
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A script is a set of commands, each command is composed of:
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375
The execution stops as soon as an expected output or an expected error is not
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When no output is specified, any ouput from the command is accepted
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and execution continue.
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If output occurs and no output is expected, the execution stops and the
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test fails. If unexpected output occurs on the standard error, then
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execution stops and the test fails.
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If an error occurs and no expected error is specified, the execution stops.
445
You can run files containing shell-like scripts with::
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$ bzr test-script <script>
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where ``<script>`` is the path to the file containing the shell-like script.
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451
The actual use of ScriptRunner within a TestCase looks something like
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456
def test_unshelve_keep(self):
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457
# some setup here
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script.run_script(self, '''
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$ bzr shelve --all -m Foo
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$ bzr shelve -q --all -m Foo
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$ bzr shelve --list
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$ bzr unshelve --keep
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$ bzr unshelve -q --keep
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$ bzr shelve --list
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You can also test commands that read user interaction::
472
def test_confirm_action(self):
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"""You can write tests that demonstrate user confirmation"""
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commands.builtin_command_registry.register(cmd_test_confirm)
475
self.addCleanup(commands.builtin_command_registry.remove, 'test-confirm')
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2>Really do it? [y/n]:
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To avoid having to specify "-q" for all commands whose output is
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irrelevant, the run_script() method may be passed the keyword argument
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``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)
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Import tariff tests
451
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-------------------
472
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This is done by running the command in a subprocess with
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``--profile-imports``. Starting a whole Python interpreter is pretty
474
slow, so we don't want exhaustive testing here, but just enough to guard
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against distinct fixed problems.
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.
477
523
Assertions about precisely what is loaded tend to be brittle so we instead
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make assertions that particular things aren't loaded.
699
745
_test_needs_features = [features.apport]
749
-----------------------
751
Translations are disabled by default in tests. If you want to test
752
that code is translated you can use the ``ZzzTranslations`` class from
755
self.overrideAttr(i18n, '_translations', ZzzTranslations())
757
And check the output strings look like ``u"zz\xe5{{output}}"``.
759
To test the gettext setup and usage you override i18n.installed back
760
to self.i18nInstalled and _translations to None, see
761
test_i18n.TestInstall.
764
Testing deprecated code
765
-----------------------
767
When code is deprecated, it is still supported for some length of time,
768
usually until the next major version. The ``applyDeprecated`` helper
769
wraps calls to deprecated code to verify that it is correctly issuing the
770
deprecation warning, and also prevents the warnings from being printed
773
Typically patches that apply the ``@deprecated_function`` decorator should
774
update the accompanying tests to use the ``applyDeprecated`` wrapper.
776
``applyDeprecated`` is defined in ``bzrlib.tests.TestCase``. See the API
777
docs for more details.
702
780
Testing exceptions and errors
703
781
-----------------------------
777
855
whether a test should be added for that particular implementation,
778
856
or for all implementations of the interface.
780
The multiplication of tests for different implementations is normally
781
accomplished by overriding the ``load_tests`` function used to load tests
782
from a module. This function typically loads all the tests, then applies
783
a TestProviderAdapter to them, which generates a longer suite containing
784
all the test variations.
786
858
See also `Per-implementation tests`_ (above).
861
Test scenarios and variations
862
-----------------------------
792
864
Some utilities are provided for generating variations of tests. This can
793
865
be used for per-implementation tests, or other cases where the same test
798
870
values to which the test should be applied. The test suite should then
799
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also provide a list of scenarios in which to run the tests.
801
Typically ``multiply_tests_from_modules`` should be called from the test
802
module's ``load_tests`` function.
873
A single *scenario* is defined by a `(name, parameter_dict)` tuple. The
874
short string name is combined with the name of the test method to form the
875
test instance name. The parameter dict is merged into the instance's
880
load_tests = load_tests_apply_scenarios
882
class TestCheckout(TestCase):
884
scenarios = multiply_scenarios(
885
VaryByRepositoryFormat(),
889
The `load_tests` declaration or definition should be near the top of the
890
file so its effect can be seen.
905
993
Please see bzrlib.treebuilder for more details.
998
PreviewTrees are based on TreeTransforms. This means they can represent
999
virtually any state that a WorkingTree can have, including unversioned files.
1000
They can be used to test the output of anything that produces TreeTransforms,
1001
such as merge algorithms and revert. They can also be used to test anything
1002
that takes arbitrary Trees as its input.
1006
# Get an empty tree to base the transform on.
1007
b = self.make_branch('.')
1008
empty_tree = b.repository.revision_tree(_mod_revision.NULL_REVISION)
1009
tt = TransformPreview(empty_tree)
1010
self.addCleanup(tt.finalize)
1011
# Empty trees don't have a root, so add it first.
1012
root = tt.new_directory('', ROOT_PARENT, 'tree-root')
1013
# Set the contents of a file.
1014
tt.new_file('new-file', root, 'contents', 'file-id')
1015
preview = tt.get_preview_tree()
1016
# Test the contents.
1017
self.assertEqual('contents', preview.get_file_text('file-id'))
1019
PreviewTrees can stack, with each tree falling back to the previous::
1021
tt2 = TransformPreview(preview)
1022
self.addCleanup(tt2.finalize)
1023
tt2.new_file('new-file2', tt2.root, 'contents2', 'file-id2')
1024
preview2 = tt2.get_preview_tree()
1025
self.assertEqual('contents', preview2.get_file_text('file-id'))
1026
self.assertEqual('contents2', preview2.get_file_text('file-id2'))
908
1029
Temporarily changing state
909
1030
~~~~~~~~~~~~~~~~~~~~~~~~~~
914
1035
self.overrideAttr(osutils, '_cached_user_encoding', 'latin-1')
1037
This should be used with discretion; sometimes it's better to make the
1038
underlying code more testable so that you don't need to rely on monkey
1042
Observing calls to a function
1043
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1045
Sometimes it's useful to observe how a function is called, typically when
1046
calling it has side effects but the side effects are not easy to observe
1047
from a test case. For instance the function may be expensive and we want
1048
to assert it is not called too many times, or it has effects on the
1049
machine that are safe to run during a test but not easy to measure. In
1050
these cases, you can use `recordCalls` which will monkey-patch in a
1051
wrapper that records when the function is called.
1054
Temporarily changing environment variables
1055
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1057
If yout test needs to temporarily change some environment variable value
1058
(which generally means you want it restored at the end), you can use::
1060
self.overrideEnv('BZR_ENV_VAR', 'new_value')
1062
If you want to remove a variable from the environment, you should use the
1063
special ``None`` value::
1065
self.overrideEnv('PATH', None)
1067
If you add a new feature which depends on a new environment variable, make
1068
sure it behaves properly when this variable is not defined (if applicable) and
1069
if you need to enforce a specific default value, check the
1070
``TestCase._cleanEnvironment`` in ``bzrlib.tests.__init__.py`` which defines a
1071
proper set of values for all tests.
949
1106
tc qdisc add dev lo root handle 1: prio
950
1107
tc qdisc add dev lo parent 1:3 handle 30: netem delay 500ms
951
tc qdisc add dev lo parent 30:1 handle 40: prio
952
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip dport 4155 0xffff flowid 1:3 handle 800::800
953
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip sport 4155 0xffff flowid 1:3 handle 800::801
1108
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip dport 4155 0xffff flowid 1:3
1109
tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip sport 4155 0xffff flowid 1:3
955
1111
and to remove this::
added
removed
doc/developers/testing.txt
