Comment 3 for bug 1204186

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