193
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.
905
870
Please see bzrlib.treebuilder for more details.
908
Temporarily changing state
909
~~~~~~~~~~~~~~~~~~~~~~~~~~
911
If your test needs to temporarily mutate some global state, and you need
912
it restored at the end, you can say for example::
914
self.overrideAttr(osutils, '_cached_user_encoding', 'latin-1')
919
Our base ``TestCase`` class provides an ``addCleanup`` method, which
920
should be used instead of ``tearDown``. All the cleanups are run when the
921
test finishes, regardless of whether it passes or fails. If one cleanup
922
fails, later cleanups are still run.
924
(The same facility is available outside of tests through
931
Generally we prefer automated testing but sometimes a manual test is the
932
right thing, especially for performance tests that want to measure elapsed
933
time rather than effort.
935
Simulating slow networks
936
------------------------
938
To get realistically slow network performance for manually measuring
939
performance, we can simulate 500ms latency (thus 1000ms round trips)::
941
$ sudo tc qdisc add dev lo root netem delay 500ms
943
Normal system behaviour is restored with ::
945
$ sudo tc qdisc del dev lo root
947
A more precise version that only filters traffic to port 4155 is::
949
tc qdisc add dev lo root handle 1: prio
950
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
957
tc filter del dev lo protocol ip parent 1: pref 3 u32
958
tc qdisc del dev lo root handle 1:
960
You can use similar code to add additional delay to a real network
961
interface, perhaps only when talking to a particular server or pointing at
962
a VM. For more information see <http://lartc.org/>.
965
873
.. |--| unicode:: U+2014
added
removed
doc/developers/testing.txt
