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# SPDX-License-Identifier: MIT
"""
Tests for `attr.converters`.
"""
from __future__ import absolute_import
import pytest
import attr
from attr import Factory, attrib
from attr.converters import default_if_none, optional, pipe, to_bool
class TestOptional(object):
"""
Tests for `optional`.
"""
def test_success_with_type(self):
"""
Wrapped converter is used as usual if value is not None.
"""
c = optional(int)
assert c("42") == 42
def test_success_with_none(self):
"""
Nothing happens if None.
"""
c = optional(int)
assert c(None) is None
def test_fail(self):
"""
Propagates the underlying conversion error when conversion fails.
"""
c = optional(int)
with pytest.raises(ValueError):
c("not_an_int")
class TestDefaultIfNone(object):
def test_missing_default(self):
"""
Raises TypeError if neither default nor factory have been passed.
"""
with pytest.raises(TypeError, match="Must pass either"):
default_if_none()
def test_too_many_defaults(self):
"""
Raises TypeError if both default and factory are passed.
"""
with pytest.raises(TypeError, match="but not both"):
default_if_none(True, lambda: 42)
def test_factory_takes_self(self):
"""
Raises ValueError if passed Factory has takes_self=True.
"""
with pytest.raises(ValueError, match="takes_self"):
default_if_none(Factory(list, takes_self=True))
@pytest.mark.parametrize("val", [1, 0, True, False, "foo", "", object()])
def test_not_none(self, val):
"""
If a non-None value is passed, it's handed down.
"""
c = default_if_none("nope")
assert val == c(val)
c = default_if_none(factory=list)
assert val == c(val)
def test_none_value(self):
"""
Default values are returned when a None is passed.
"""
c = default_if_none(42)
assert 42 == c(None)
def test_none_factory(self):
"""
Factories are used if None is passed.
"""
c = default_if_none(factory=list)
assert [] == c(None)
c = default_if_none(default=Factory(list))
assert [] == c(None)
class TestPipe(object):
def test_success(self):
"""
Succeeds if all wrapped converters succeed.
"""
c = pipe(str, to_bool, bool)
assert True is c("True") is c(True)
def test_fail(self):
"""
Fails if any wrapped converter fails.
"""
c = pipe(str, to_bool)
# First wrapped converter fails:
with pytest.raises(ValueError):
c(33)
# Last wrapped converter fails:
with pytest.raises(ValueError):
c("33")
def test_sugar(self):
"""
`pipe(c1, c2, c3)` and `[c1, c2, c3]` are equivalent.
"""
@attr.s
class C(object):
a1 = attrib(default="True", converter=pipe(str, to_bool, bool))
a2 = attrib(default=True, converter=[str, to_bool, bool])
c = C()
assert True is c.a1 is c.a2
class TestToBool(object):
def test_unhashable(self):
"""
Fails if value is unhashable.
"""
with pytest.raises(ValueError, match="Cannot convert value to bool"):
to_bool([])
def test_truthy(self):
"""
Fails if truthy values are incorrectly converted.
"""
assert to_bool("t")
assert to_bool("yes")
assert to_bool("on")
def test_falsy(self):
"""
Fails if falsy values are incorrectly converted.
"""
assert not to_bool("f")
assert not to_bool("no")
assert not to_bool("off")