Trying a solution for bug: http://issues.mediagoblin.org/ticket/146

messages.py

# GNU MediaGoblin -- federated, autonomous media hosting
# Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from mediagoblin.tools import common

DEBUG = 'debug'
INFO = 'info'
SUCCESS = 'success'
WARNING = 'warning'
ERROR = 'error'

ADD_MESSAGE_TEST = []

def add_message(request, level, text):
    messages = request.session.setdefault('messages', [])
    messages.append({'level': level, 'text': text})

    if common.TESTS_ENABLED:
        ADD_MESSAGE_TEST.append(messages)

    request.session.save()

def fetch_messages(request, clear_from_session=True):
    messages = request.session.get('messages')
    if messages and clear_from_session:
        # Save that we removed the messages from the session
        request.session['messages'] = []
        request.session.save()

    return messages
    
    
def clear_add_message():
    global ADD_MESSAGE_TEST
    ADD_MESSAGE_TEST = []
    

test_messages.py

# GNU MediaGoblin -- federated, autonomous media hosting
# Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from mediagoblin.messages import fetch_messages, add_message
from mediagoblin.tools import template


def test_messages(test_app):
    """
    Added messages should show up in the request.session,
    fetched messages should be the same as the added ones,
    and fetching should clear the message list.
    """
    # Aquire a request object
    test_app.get('/')
    context = template.TEMPLATE_TEST_CONTEXT['mediagoblin/root.html']
    request = context['request']

    # The message queue should be empty
    assert request.session.get('messages', []) == []

    # First of all, we should clear the messages queue
    messages.clear_add_message()
    # Adding a message should modify the session accordingly
    add_message(request, 'herp_derp', 'First!')
    test_msg_queue = [{'text': 'First!', 'level': 'herp_derp'}]
    
    # Alternative tests to the following, test divided in two steps:
    # assert request.session['messages'] == test_msg_queue
    
    # I'm considering there is no concurrence for ADD_MESSAGE_TEST (because
    # we are just running tests, so I imagine anyone is trying to call
    # add_message() at the same time... in this way I'm getting the last
    # message added into the list.
    
    # 1. Tests if add_message worked 
    assert messages.ADD_MESSAGE_TEST[-1] == test_msg_queue
    # 2. Tests if add_message updated session information
    assert messages.ADD_MESSAGE_TEST[-1] == request.session['messages']

    # fetch_messages should return and empty the queue
    assert fetch_messages(request) == test_msg_queue
    assert request.session.get('messages') == []