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# (C) Copyright 2005-2023 Enthought, Inc., Austin, TX
# All rights reserved.
#
# 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
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
import unittest
from traits.api import Float, HasTraits, Int, List
class Foo(HasTraits):
x = Float
y_changes = List
def _y_changed(self, new):
self.y_changes.append(new)
class TestDynamicTraitDefinition(unittest.TestCase):
""" Test demonstrating special change events using the 'event' metadata.
"""
def test_add_trait(self):
foo = Foo(x=3)
foo.add_trait("y", Int)
self.assertTrue(hasattr(foo, "y"))
self.assertEqual(type(foo.y), int)
foo.y = 4
self.assertEqual(foo.y_changes, [4])
def test_remove_trait(self):
foo = Foo(x=3)
# We can't remove a "statically" added trait (i.e., a trait defined
# in the Foo class).
result = foo.remove_trait("x")
self.assertFalse(result)
# We can remove dynamically added traits.
foo.add_trait("y", Int)
foo.y = 70
result = foo.remove_trait("y")
self.assertTrue(result)
self.assertFalse(hasattr(foo, "y"))
foo.y = 10
self.assertEqual(foo.y_changes, [70])
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