Test test_get_bind_addr_default_value picks up port value from system config file

[Stuart McLaren]

When I run the tests, eg with

$ tox -epy27

I see the following error:

======================================================================
FAIL: glance.tests.unit.common.test_wsgi.JSONRequestDeserializerTest.test_get_bind_addr_default_value
----------------------------------------------------------------------
_StringException: Traceback (most recent call last):
  File "/home/ubuntu/git/glance.new/glance/glance/tests/unit/common/test_wsgi.py", line 250, in test_get_bind_addr_default_value
    self.assertEqual(expected, actual)
  File "/home/ubuntu/git/glance.new/glance/.tox/venv/local/lib/python2.7/site-packages/testtools/testcase.py", line 322, in assertEqual
    self.assertThat(observed, matcher, message)
  File "/home/ubuntu/git/glance.new/glance/.tox/venv/local/lib/python2.7/site-packages/testtools/testcase.py", line 417, in assertThat
    raise MismatchError(matchee, matcher, mismatch, verbose)
MismatchError: ('0.0.0.0', '123456') != ('0.0.0.0', 9291)

Slowest 5 tests took 70.04 secs:
    21.68 TestScrubber.test_scrubber_delete_handles_exception
    21.66 TestScrubber.test_scrubber_app
    16.27 TestScrubber.test_delayed_delete
    6.56 TestBinGlanceCacheManage.test_queue
    3.87 TestRootApi.test_version_configurations
----------------------------------------------------------------------
Ran 1530 tests in 300.360s

Port 9291 [sic] is being picked up from /etc/glance/glance-api.conf

$ grep 9291 /etc/glance/glance-api.conf
bind_port = 9291

The unit test should be independent of any config files present on the system.

[Stuart McLaren (stuart-mclaren)]

Funnily enough I'm only able to reproduce this by running all the tests, eg if I run:

$ tox -evenv -- nosetests --tests=glance.tests.unit.common.test_wsgi:JSONRequestDeserializerTest.test_get_bind_addr_default_value
GLOB sdist-make: /home/ubuntu/git/glance.new/glance/setup.py
venv inst-nodeps: /home/ubuntu/git/glance.new/glance/.tox/dist/glance-2013.2.a20.g0f669d5.zip
venv runtests: commands[0] | nosetests --tests=glance.tests.unit.common.test_wsgi:JSONRequestDeserializerTest.test_get_bind_addr_default_value

JSONRequestDeserializerTest
    test_get_bind_addr_default_value OK 0.00

----------------------------------------------------------------------
Ran 1 test in 0.004s

OK
__________________________________________________________________________________ summary ___________________________________________________________________________________
  venv: commands succeeded
  congratulations :)

It seems to work ok.

Just
$ tox -evenv
reproduces

I'm not sure if there's a 'better' way to run a single test which would reproduce without having to run all tests.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/43579

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/43579
Committed: http://github.com/openstack/glance/commit/de22b642f79b5af589ccd437d36b883a6a52c475
Submitter: Jenkins
Branch: master

commit de22b642f79b5af589ccd437d36b883a6a52c475
Author: Kui Shi <email address hidden>
Date: Sat Aug 24 16:23:51 2013 +0800

    test failure induced by reading system config file

    run run_tests.sh or tox to test the glance code, it will get
    following failure:
    test_get_bind_addr_default_value
    test_get_path_non_exist

    Analysis
    --------
    The root cause is resided in "glance/tests/unit/api/test_cmd.py".
    In TestGlanceApiCmd.setUp, the sys.argv is overrided to ['glance-api'].
    Since sys.argv is "global" variable, and this test entry it run
    firstly by nosetests while running tests in "glance/tests/unit"(since
    nosetests search test items alphabetically), the other test entries
    will inherit the sys.argv value ['glance-api']. Finally the system
    config file "/etc/glance/glance-api.conf" is read in "setUp" via
    oslo.config.cfg:ConfigOpts.__call__ -> _pre_setup -> find_config_files.
    CONF.bind_port and CONF.bind_host is set to the value reading from
    system config file: /etc/glance/glance-api.conf.

    A simplied call backtrace:
    TestGlanceApiCmd.setUp --> sys.argv = ['glance-api']
     ->JSONRequestDeserializerTest.setUp
      ->glance/common/config.py:parse_args
       ->oslo.config.cfg:ConfigOpts.__call__
        ->CONF.bind_port CONF.bind_host is set

    wsgi.get_bind_addr() will read the CONF.bind_port and CONF.bind_host
    to return value. if system config file is not read, CONF.bind_host
    is set to "0.0.0.0", CONF.bind_port is not set. wsgi.get_bind_addr()
    will return the expected value. This is the reason that individual
    test of test_get_bind_addr_default_value got passed, but failed while
    testing all.

    The failure of test_get_path_non_exist is induced by same reason.

    Test case should clear up the setting in tearDown(), especially the
    "global" setting, e.g. sys.argv.

    Solution
    --------
    The solution is simple:
    In class TestGlanceApiCmd, add a private variable to backup the
    sys.argv in setUp(), and restore it in tearDown().

    Test method
    -----------
    $ ./run_tests.sh

    $ tox -evenv -- nosetests \
    --tests=glance.tests.unit.common.test_config:TestPasteApp

    tox -evenv -- nosetests
    --tests=glance.tests.unit.common.test_wsgi:JSONRequestDeserializerTest

    Fixes Bug #1204186

    Change-Id: I2dac8e506fa794d1faa9509258936d78e2f981d8