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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 (
Bytes, DefaultValue, Float, HasTraits, Instance, Int, List, Str,
TraitError, TraitType, Type, Union)
class CustomClass(HasTraits):
value = Int
class CustomStrType(TraitType):
#: The default value type to use.
default_value_type = DefaultValue.constant
#: The default value.
default_value = "a string value"
def validate(self, obj, name, value):
if not isinstance(value, Str):
return value
self.error(obj, name, value)
class TestUnion(unittest.TestCase):
def test_union_incompatible_trait(self):
with self.assertRaises(ValueError) as exception_context:
Union(Str(), "none")
self.assertEqual(
str(exception_context.exception),
"Union trait declaration expects a trait type or an instance of "
"trait type or None, but got 'none' instead"
)
def test_list_trait_types(self):
class TestClass(HasTraits):
int_or_str_type = Union(Type, Int, Str)
TestClass(int_or_str_type=3)
TestClass(int_or_str_type="3.5")
with self.assertRaises(TraitError):
TestClass(int_or_str_type=3.5)
with self.assertRaises(TraitError):
TestClass(int_or_str_type=Int(3))
def test_malformed_declaration(self):
with self.assertRaises(ValueError):
class TestClass(HasTraits):
a = Union(int, Float)
TestClass(a=2.4)
with self.assertRaises(ValueError):
class TestClass(HasTraits):
a = Union([1, 2], Float)
TestClass(a=2.4)
def test_list_trait_instances(self):
class TestClass(HasTraits):
float_or_str_obj = Union(Instance(Float), Instance(Str))
TestClass(float_or_str_obj=Float(3.5))
TestClass(float_or_str_obj=Str("3.5"))
with self.assertRaises(TraitError):
TestClass(float_or_str_obj=Float)
with self.assertRaises(TraitError):
TestClass(float_or_str_obj=3.5)
def test_union_with_none(self):
class TestClass(HasTraits):
int_or_none = Union(None, Int)
TestClass(int_or_none=None)
def test_union_unspecified_arguments(self):
class TestClass(HasTraits):
none = Union()
TestClass(none=None)
def test_default_value(self):
class TestClass(HasTraits):
atr = Union(Int(3), Float(4.1), Str("Something"))
self.assertEqual(TestClass().atr, 3)
class TestClass(HasTraits):
atr = Union(
Int(3), Float(4.1), Str("Something"),
default_value="XYZ",
)
self.assertEqual(TestClass().atr, "XYZ")
class TestClass(HasTraits):
atr = Union()
self.assertEqual(TestClass().atr, None)
class TestClass(HasTraits):
atr = Union(None)
self.assertEqual(TestClass().atr, None)
def test_default_raise_error(self):
# If 'default' is defined, it could be caused by migration from
# ``Either``. Raise an error to aid migrations from ``Either``
# to ``Union``
with self.assertRaises(ValueError) as exception_context:
Union(Int(), Float(), default=1.0)
self.assertEqual(
str(exception_context.exception),
"Union default value should be set via 'default_value', not "
"'default'."
)
def test_inner_traits(self):
class TestClass(HasTraits):
atr = Union(Float, Int, Str)
obj = TestClass()
t1, t2, t3 = obj.trait('atr').inner_traits
self.assertEqual(type(t1.trait_type), Float)
self.assertEqual(type(t2.trait_type), Int)
self.assertEqual(type(t3.trait_type), Str)
def test_union_user_defined_class(self):
class TestClass(HasTraits):
obj = Union(Instance(CustomClass), Int)
TestClass(obj=CustomClass(value=5))
TestClass(obj=5)
with self.assertRaises(TraitError):
TestClass(obj=CustomClass)
def test_union_user_defined_type(self):
class TestClass(HasTraits):
type_value = Union(CustomStrType, Int)
TestClass(type_value="new string")
def test_notification(self):
class TestClass(HasTraits):
union_attr = Union(Int)
shadow_union_trait = None
def _union_attr_changed(self, new):
self.shadow_union_trait = new
obj = TestClass(union_attr=-1)
obj.union_attr = 1
self.assertEqual(obj.shadow_union_trait, 1)
def test_extending_union_trait(self):
class UnionAllowStr(Union):
def validate(self, obj, name, value):
if isinstance(value, str):
return value
return super().validate(obj, name, value)
class TestClass(HasTraits):
s = UnionAllowStr(Int, Float)
TestClass(s="sdf")
def test_list_inside_union_default(self):
class HasUnionWithList(HasTraits):
foo = Union(List(Int), Str)
has_union = HasUnionWithList()
value = has_union.foo
self.assertIsInstance(value, list)
with self.assertRaises(TraitError):
value.append("not an integer")
def test_constant_default(self):
# Exercise the branch where the default is constant.
class HasUnionWithList(HasTraits):
foo = Union(Int(23), Float)
nested = Union(Union(Str(), Bytes()), Union(Int(), Float(), None))
has_union = HasUnionWithList()
value = has_union.foo
self.assertEqual(value, 23)
self.assertEqual(
has_union.trait("foo").default_value(),
(DefaultValue.constant, 23),
)
self.assertEqual(
has_union.trait("nested").default_value(),
(DefaultValue.constant, ""),
)
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