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#
#  Copyright (c) 2007, Enthought, Inc.
#  All rights reserved.
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#  This software is provided without warranty under the terms of the BSD
#  license included in /LICENSE.txt and may be redistributed only
#  under the conditions described in the aforementioned license.  The license
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""" Test cases for dictionary (Dict) traits. """


from __future__ import absolute_import

from traits.testing.unittest_tools import unittest

from ..api import on_trait_change, Dict, Event, HasTraits, Str


# fixme: We'd like to use a callable instance for the listener so that we
# can maintain state, but traits barfs trying to determine the signature 8^()
def create_listener():
    """ Create a listener for testing trait notifications. """

    def listener(obj, trait_name, old, new):

        listener.obj        = obj
        listener.trait_name = trait_name
        listener.new        = new
        listener.old        = old
        listener.called     += 1

        return

    listener.initialize = lambda : initialize_listener(listener)
    
    return initialize_listener(listener)

def initialize_listener(listener):
    """ Initialize a listener so it looks like it hasn't been called.

    This allows us to re-use the listener without having to create and
    wire-up a new one.

    """

    listener.obj        = None
    listener.trait_name = None
    listener.old        = None
    listener.new        = None
    listener.called     = 0
    
    return listener # For convenience



class DictTestCase(unittest.TestCase):
    """ Test cases for dictionary (Dict) traits. """

    def test_modified_event(self):

        class Foo(HasTraits):
            name     = Str
            modified = Event
            
            @on_trait_change('name')
            def _fire_modified_event(self):
                self.modified = True
                return
        
        class Bar(HasTraits):
            foos     = Dict(Str, Foo)
            modified = Event
            
            @on_trait_change('foos_items,foos.modified')
            def _fire_modified_event(self, obj, trait_name, old, new):
                self.modified = True
                return

        bar = Bar()
        listener = create_listener()
        bar.on_trait_change(listener, 'modified')

        # Assign a completely new dictionary.
        bar.foos = {'dino' : Foo(name='dino')}
        self.assertEqual(1, listener.called)
        self.assertEqual('modified', listener.trait_name)
        
        # Add an item to an existing dictionary.
        listener.initialize()
        fred = Foo(name='fred')
        bar.foos['fred'] = fred
        self.assertEqual(1, listener.called)
        self.assertEqual('modified', listener.trait_name)

        # Modify an item already in the dictionary.
        listener.initialize()
        fred.name = 'barney'
        self.assertEqual(1, listener.called)
        self.assertEqual('modified', listener.trait_name)

        # Overwrite an item in the dictionary. This is the one that fails!
        listener.initialize()
        bar.foos['fred'] = Foo(name='wilma')
        self.assertEqual(1, listener.called)
        self.assertEqual('modified', listener.trait_name)

        return


if __name__ == '__main__':
    unittest.main()

#### EOF ######################################################################
