attrs/tests/test_validators.py

111 lines
2.5 KiB
Python

"""
Tests for `attr.validators`.
"""
from __future__ import absolute_import, division, print_function
import pytest
import zope.interface
from attr.validators import instance_of, provides
from attr._compat import TYPE
from . import simple_attr
class TestInstanceOf(object):
"""
Tests for `instance_of`.
"""
def test_success(self):
"""
Nothing happens if types match.
"""
v = instance_of(int)
v(None, simple_attr("test"), 42)
def test_subclass(self):
"""
Subclasses are accepted too.
"""
v = instance_of(int)
# yep, bools are a subclass of int :(
v(None, simple_attr("test"), True)
def test_fail(self):
"""
Raises `TypeError` on wrong types.
"""
v = instance_of(int)
a = simple_attr("test")
with pytest.raises(TypeError) as e:
v(None, a, "42")
assert (
"'test' must be <{type} 'int'> (got '42' that is a <{type} "
"'str'>).".format(type=TYPE),
a, int, "42",
) == e.value.args
def test_repr(self):
"""
Returned validator has a useful `__repr__`.
"""
v = instance_of(int)
assert (
"<instance_of validator for type <{type} 'int'>>"
.format(type=TYPE)
) == repr(v)
class IFoo(zope.interface.Interface):
"""
An interface.
"""
def f():
"""
A function called f.
"""
class TestProvides(object):
"""
Tests for `provides`.
"""
def test_success(self):
"""
Nothing happens if value provides requested interface.
"""
@zope.interface.implementer(IFoo)
class C(object):
def f(self):
pass
v = provides(IFoo)
v(None, simple_attr("x"), C())
def test_fail(self):
"""
Raises `TypeError` if interfaces isn't provided by value.
"""
value = object()
a = simple_attr("x")
v = provides(IFoo)
with pytest.raises(TypeError) as e:
v(None, a, value)
assert (
"'x' must provide {interface!r} which {value!r} doesn't."
.format(interface=IFoo, value=value),
a, IFoo, value,
) == e.value.args
def test_repr(self):
"""
Returned validator has a useful `__repr__`.
"""
v = provides(IFoo)
assert (
"<provides validator for interface {interface!r}>"
.format(interface=IFoo)
) == repr(v)