Staging
v0.5.1
v0.5.1
https://github.com/python/cpython
Tip revision: 90a6785f6328bd27d307ce20202d6b34aa0cc10b authored by Ned Deily on 05 December 2017, 08:27:19 UTC
Bump to 3.7.0a3
Bump to 3.7.0a3
Tip revision: 90a6785
test_dataclasses.py
from dataclasses import (
dataclass, field, FrozenInstanceError, fields, asdict, astuple,
make_dataclass, replace, InitVar, Field
)
import pickle
import inspect
import unittest
from unittest.mock import Mock
from typing import ClassVar, Any, List, Union, Tuple, Dict, Generic, TypeVar
from collections import deque, OrderedDict, namedtuple
# Just any custom exception we can catch.
class CustomError(Exception): pass
class TestCase(unittest.TestCase):
def test_no_fields(self):
@dataclass
class C:
pass
o = C()
self.assertEqual(len(fields(C)), 0)
def test_one_field_no_default(self):
@dataclass
class C:
x: int
o = C(42)
self.assertEqual(o.x, 42)
def test_named_init_params(self):
@dataclass
class C:
x: int
o = C(x=32)
self.assertEqual(o.x, 32)
def test_two_fields_one_default(self):
@dataclass
class C:
x: int
y: int = 0
o = C(3)
self.assertEqual((o.x, o.y), (3, 0))
# Non-defaults following defaults.
with self.assertRaisesRegex(TypeError,
"non-default argument 'y' follows "
"default argument"):
@dataclass
class C:
x: int = 0
y: int
# A derived class adds a non-default field after a default one.
with self.assertRaisesRegex(TypeError,
"non-default argument 'y' follows "
"default argument"):
@dataclass
class B:
x: int = 0
@dataclass
class C(B):
y: int
# Override a base class field and add a default to
# a field which didn't use to have a default.
with self.assertRaisesRegex(TypeError,
"non-default argument 'y' follows "
"default argument"):
@dataclass
class B:
x: int
y: int
@dataclass
class C(B):
x: int = 0
def test_overwriting_init(self):
with self.assertRaisesRegex(TypeError,
'Cannot overwrite attribute __init__ '
'in C'):
@dataclass
class C:
x: int
def __init__(self, x):
self.x = 2 * x
@dataclass(init=False)
class C:
x: int
def __init__(self, x):
self.x = 2 * x
self.assertEqual(C(5).x, 10)
def test_overwriting_repr(self):
with self.assertRaisesRegex(TypeError,
'Cannot overwrite attribute __repr__ '
'in C'):
@dataclass
class C:
x: int
def __repr__(self):
pass
@dataclass(repr=False)
class C:
x: int
def __repr__(self):
return 'x'
self.assertEqual(repr(C(0)), 'x')
def test_overwriting_cmp(self):
with self.assertRaisesRegex(TypeError,
'Cannot overwrite attribute __eq__ '
'in C'):
# This will generate the comparison functions, make sure we can't
# overwrite them.
@dataclass(hash=False, frozen=False)
class C:
x: int
def __eq__(self):
pass
@dataclass(order=False, eq=False)
class C:
x: int
def __eq__(self, other):
return True
self.assertEqual(C(0), 'x')
def test_overwriting_hash(self):
with self.assertRaisesRegex(TypeError,
'Cannot overwrite attribute __hash__ '
'in C'):
@dataclass(frozen=True)
class C:
x: int
def __hash__(self):
pass
@dataclass(frozen=True,hash=False)
class C:
x: int
def __hash__(self):
return 600
self.assertEqual(hash(C(0)), 600)
with self.assertRaisesRegex(TypeError,
'Cannot overwrite attribute __hash__ '
'in C'):
@dataclass(frozen=True)
class C:
x: int
def __hash__(self):
pass
@dataclass(frozen=True, hash=False)
class C:
x: int
def __hash__(self):
return 600
self.assertEqual(hash(C(0)), 600)
def test_overwriting_frozen(self):
# frozen uses __setattr__ and __delattr__
with self.assertRaisesRegex(TypeError,
'Cannot overwrite attribute __setattr__ '
'in C'):
@dataclass(frozen=True)
class C:
x: int
def __setattr__(self):
pass
with self.assertRaisesRegex(TypeError,
'Cannot overwrite attribute __delattr__ '
'in C'):
@dataclass(frozen=True)
class C:
x: int
def __delattr__(self):
pass
@dataclass(frozen=False)
class C:
x: int
def __setattr__(self, name, value):
self.__dict__['x'] = value * 2
self.assertEqual(C(10).x, 20)
def test_overwrite_fields_in_derived_class(self):
# Note that x from C1 replaces x in Base, but the order remains
# the same as defined in Base.
@dataclass
class Base:
x: Any = 15.0
y: int = 0
@dataclass
class C1(Base):
z: int = 10
x: int = 15
o = Base()
self.assertEqual(repr(o), 'TestCase.test_overwrite_fields_in_derived_class.<locals>.Base(x=15.0, y=0)')
o = C1()
self.assertEqual(repr(o), 'TestCase.test_overwrite_fields_in_derived_class.<locals>.C1(x=15, y=0, z=10)')
o = C1(x=5)
self.assertEqual(repr(o), 'TestCase.test_overwrite_fields_in_derived_class.<locals>.C1(x=5, y=0, z=10)')
def test_field_named_self(self):
@dataclass
class C:
self: str
c=C('foo')
self.assertEqual(c.self, 'foo')
# Make sure the first parameter is not named 'self'.
sig = inspect.signature(C.__init__)
first = next(iter(sig.parameters))
self.assertNotEqual('self', first)
# But we do use 'self' if no field named self.
@dataclass
class C:
selfx: str
# Make sure the first parameter is named 'self'.
sig = inspect.signature(C.__init__)
first = next(iter(sig.parameters))
self.assertEqual('self', first)
def test_repr(self):
@dataclass
class B:
x: int
@dataclass
class C(B):
y: int = 10
o = C(4)
self.assertEqual(repr(o), 'TestCase.test_repr.<locals>.C(x=4, y=10)')
@dataclass
class D(C):
x: int = 20
self.assertEqual(repr(D()), 'TestCase.test_repr.<locals>.D(x=20, y=10)')
@dataclass
class C:
@dataclass
class D:
i: int
@dataclass
class E:
pass
self.assertEqual(repr(C.D(0)), 'TestCase.test_repr.<locals>.C.D(i=0)')
self.assertEqual(repr(C.E()), 'TestCase.test_repr.<locals>.C.E()')
def test_0_field_compare(self):
# Ensure that order=False is the default.
@dataclass
class C0:
pass
@dataclass(order=False)
class C1:
pass
for cls in [C0, C1]:
with self.subTest(cls=cls):
self.assertEqual(cls(), cls())
for idx, fn in enumerate([lambda a, b: a < b,
lambda a, b: a <= b,
lambda a, b: a > b,
lambda a, b: a >= b]):
with self.subTest(idx=idx):
with self.assertRaisesRegex(TypeError,
f"not supported between instances of '{cls.__name__}' and '{cls.__name__}'"):
fn(cls(), cls())
@dataclass(order=True)
class C:
pass
self.assertLessEqual(C(), C())
self.assertGreaterEqual(C(), C())
def test_1_field_compare(self):
# Ensure that order=False is the default.
@dataclass
class C0:
x: int
@dataclass(order=False)
class C1:
x: int
for cls in [C0, C1]:
with self.subTest(cls=cls):
self.assertEqual(cls(1), cls(1))
self.assertNotEqual(cls(0), cls(1))
for idx, fn in enumerate([lambda a, b: a < b,
lambda a, b: a <= b,
lambda a, b: a > b,
lambda a, b: a >= b]):
with self.subTest(idx=idx):
with self.assertRaisesRegex(TypeError,
f"not supported between instances of '{cls.__name__}' and '{cls.__name__}'"):
fn(cls(0), cls(0))
@dataclass(order=True)
class C:
x: int
self.assertLess(C(0), C(1))
self.assertLessEqual(C(0), C(1))
self.assertLessEqual(C(1), C(1))
self.assertGreater(C(1), C(0))
self.assertGreaterEqual(C(1), C(0))
self.assertGreaterEqual(C(1), C(1))
def test_simple_compare(self):
# Ensure that order=False is the default.
@dataclass
class C0:
x: int
y: int
@dataclass(order=False)
class C1:
x: int
y: int
for cls in [C0, C1]:
with self.subTest(cls=cls):
self.assertEqual(cls(0, 0), cls(0, 0))
self.assertEqual(cls(1, 2), cls(1, 2))
self.assertNotEqual(cls(1, 0), cls(0, 0))
self.assertNotEqual(cls(1, 0), cls(1, 1))
for idx, fn in enumerate([lambda a, b: a < b,
lambda a, b: a <= b,
lambda a, b: a > b,
lambda a, b: a >= b]):
with self.subTest(idx=idx):
with self.assertRaisesRegex(TypeError,
f"not supported between instances of '{cls.__name__}' and '{cls.__name__}'"):
fn(cls(0, 0), cls(0, 0))
@dataclass(order=True)
class C:
x: int
y: int
for idx, fn in enumerate([lambda a, b: a == b,
lambda a, b: a <= b,
lambda a, b: a >= b]):
with self.subTest(idx=idx):
self.assertTrue(fn(C(0, 0), C(0, 0)))
for idx, fn in enumerate([lambda a, b: a < b,
lambda a, b: a <= b,
lambda a, b: a != b]):
with self.subTest(idx=idx):
self.assertTrue(fn(C(0, 0), C(0, 1)))
self.assertTrue(fn(C(0, 1), C(1, 0)))
self.assertTrue(fn(C(1, 0), C(1, 1)))
for idx, fn in enumerate([lambda a, b: a > b,
lambda a, b: a >= b,
lambda a, b: a != b]):
with self.subTest(idx=idx):
self.assertTrue(fn(C(0, 1), C(0, 0)))
self.assertTrue(fn(C(1, 0), C(0, 1)))
self.assertTrue(fn(C(1, 1), C(1, 0)))
def test_compare_subclasses(self):
# Comparisons fail for subclasses, even if no fields
# are added.
@dataclass
class B:
i: int
@dataclass
class C(B):
pass
for idx, (fn, expected) in enumerate([(lambda a, b: a == b, False),
(lambda a, b: a != b, True)]):
with self.subTest(idx=idx):
self.assertEqual(fn(B(0), C(0)), expected)
for idx, fn in enumerate([lambda a, b: a < b,
lambda a, b: a <= b,
lambda a, b: a > b,
lambda a, b: a >= b]):
with self.subTest(idx=idx):
with self.assertRaisesRegex(TypeError,
"not supported between instances of 'B' and 'C'"):
fn(B(0), C(0))
def test_0_field_hash(self):
@dataclass(hash=True)
class C:
pass
self.assertEqual(hash(C()), hash(()))
def test_1_field_hash(self):
@dataclass(hash=True)
class C:
x: int
self.assertEqual(hash(C(4)), hash((4,)))
self.assertEqual(hash(C(42)), hash((42,)))
def test_hash(self):
@dataclass(hash=True)
class C:
x: int
y: str
self.assertEqual(hash(C(1, 'foo')), hash((1, 'foo')))
def test_no_hash(self):
@dataclass(hash=None)
class C:
x: int
with self.assertRaisesRegex(TypeError,
"unhashable type: 'C'"):
hash(C(1))
def test_hash_rules(self):
# There are 24 cases of:
# hash=True/False/None
# eq=True/False
# order=True/False
# frozen=True/False
for (hash, eq, order, frozen, result ) in [
(False, False, False, False, 'absent'),
(False, False, False, True, 'absent'),
(False, False, True, False, 'exception'),
(False, False, True, True, 'exception'),
(False, True, False, False, 'absent'),
(False, True, False, True, 'absent'),
(False, True, True, False, 'absent'),
(False, True, True, True, 'absent'),
(True, False, False, False, 'fn'),
(True, False, False, True, 'fn'),
(True, False, True, False, 'exception'),
(True, False, True, True, 'exception'),
(True, True, False, False, 'fn'),
(True, True, False, True, 'fn'),
(True, True, True, False, 'fn'),
(True, True, True, True, 'fn'),
(None, False, False, False, 'absent'),
(None, False, False, True, 'absent'),
(None, False, True, False, 'exception'),
(None, False, True, True, 'exception'),
(None, True, False, False, 'none'),
(None, True, False, True, 'fn'),
(None, True, True, False, 'none'),
(None, True, True, True, 'fn'),
]:
with self.subTest(hash=hash, eq=eq, order=order, frozen=frozen):
if result == 'exception':
with self.assertRaisesRegex(ValueError, 'eq must be true if order is true'):
@dataclass(hash=hash, eq=eq, order=order, frozen=frozen)
class C:
pass
else:
@dataclass(hash=hash, eq=eq, order=order, frozen=frozen)
class C:
pass
# See if the result matches what's expected.
if result == 'fn':
# __hash__ contains the function we generated.
self.assertIn('__hash__', C.__dict__)
self.assertIsNotNone(C.__dict__['__hash__'])
elif result == 'absent':
# __hash__ is not present in our class.
self.assertNotIn('__hash__', C.__dict__)
elif result == 'none':
# __hash__ is set to None.
self.assertIn('__hash__', C.__dict__)
self.assertIsNone(C.__dict__['__hash__'])
else:
assert False, f'unknown result {result!r}'
def test_eq_order(self):
for (eq, order, result ) in [
(False, False, 'neither'),
(False, True, 'exception'),
(True, False, 'eq_only'),
(True, True, 'both'),
]:
with self.subTest(eq=eq, order=order):
if result == 'exception':
with self.assertRaisesRegex(ValueError, 'eq must be true if order is true'):
@dataclass(eq=eq, order=order)
class C:
pass
else:
@dataclass(eq=eq, order=order)
class C:
pass
if result == 'neither':
self.assertNotIn('__eq__', C.__dict__)
self.assertNotIn('__ne__', C.__dict__)
self.assertNotIn('__lt__', C.__dict__)
self.assertNotIn('__le__', C.__dict__)
self.assertNotIn('__gt__', C.__dict__)
self.assertNotIn('__ge__', C.__dict__)
elif result == 'both':
self.assertIn('__eq__', C.__dict__)
self.assertIn('__ne__', C.__dict__)
self.assertIn('__lt__', C.__dict__)
self.assertIn('__le__', C.__dict__)
self.assertIn('__gt__', C.__dict__)
self.assertIn('__ge__', C.__dict__)
elif result == 'eq_only':
self.assertIn('__eq__', C.__dict__)
self.assertIn('__ne__', C.__dict__)
self.assertNotIn('__lt__', C.__dict__)
self.assertNotIn('__le__', C.__dict__)
self.assertNotIn('__gt__', C.__dict__)
self.assertNotIn('__ge__', C.__dict__)
else:
assert False, f'unknown result {result!r}'
def test_field_no_default(self):
@dataclass
class C:
x: int = field()
self.assertEqual(C(5).x, 5)
with self.assertRaisesRegex(TypeError,
r"__init__\(\) missing 1 required "
"positional argument: 'x'"):
C()
def test_field_default(self):
default = object()
@dataclass
class C:
x: object = field(default=default)
self.assertIs(C.x, default)
c = C(10)
self.assertEqual(c.x, 10)
# If we delete the instance attribute, we should then see the
# class attribute.
del c.x
self.assertIs(c.x, default)
self.assertIs(C().x, default)
def test_not_in_repr(self):
@dataclass
class C:
x: int = field(repr=False)
with self.assertRaises(TypeError):
C()
c = C(10)
self.assertEqual(repr(c), 'TestCase.test_not_in_repr.<locals>.C()')
@dataclass
class C:
x: int = field(repr=False)
y: int
c = C(10, 20)
self.assertEqual(repr(c), 'TestCase.test_not_in_repr.<locals>.C(y=20)')
def test_not_in_compare(self):
@dataclass
class C:
x: int = 0
y: int = field(compare=False, default=4)
self.assertEqual(C(), C(0, 20))
self.assertEqual(C(1, 10), C(1, 20))
self.assertNotEqual(C(3), C(4, 10))
self.assertNotEqual(C(3, 10), C(4, 10))
def test_hash_field_rules(self):
# Test all 6 cases of:
# hash=True/False/None
# compare=True/False
for (hash_val, compare, result ) in [
(True, False, 'field' ),
(True, True, 'field' ),
(False, False, 'absent'),
(False, True, 'absent'),
(None, False, 'absent'),
(None, True, 'field' ),
]:
with self.subTest(hash_val=hash_val, compare=compare):
@dataclass(hash=True)
class C:
x: int = field(compare=compare, hash=hash_val, default=5)
if result == 'field':
# __hash__ contains the field.
self.assertEqual(C(5).__hash__(), hash((5,)))
elif result == 'absent':
# The field is not present in the hash.
self.assertEqual(C(5).__hash__(), hash(()))
else:
assert False, f'unknown result {result!r}'
def test_init_false_no_default(self):
# If init=False and no default value, then the field won't be
# present in the instance.
@dataclass
class C:
x: int = field(init=False)
self.assertNotIn('x', C().__dict__)
@dataclass
class C:
x: int
y: int = 0
z: int = field(init=False)
t: int = 10
self.assertNotIn('z', C(0).__dict__)
self.assertEqual(vars(C(5)), {'t': 10, 'x': 5, 'y': 0})
def test_class_marker(self):
@dataclass
class C:
x: int
y: str = field(init=False, default=None)
z: str = field(repr=False)
the_fields = fields(C)
# the_fields is a tuple of 3 items, each value
# is in __annotations__.
self.assertIsInstance(the_fields, tuple)
for f in the_fields:
self.assertIs(type(f), Field)
self.assertIn(f.name, C.__annotations__)
self.assertEqual(len(the_fields), 3)
self.assertEqual(the_fields[0].name, 'x')
self.assertEqual(the_fields[0].type, int)
self.assertFalse(hasattr(C, 'x'))
self.assertTrue (the_fields[0].init)
self.assertTrue (the_fields[0].repr)
self.assertEqual(the_fields[1].name, 'y')
self.assertEqual(the_fields[1].type, str)
self.assertIsNone(getattr(C, 'y'))
self.assertFalse(the_fields[1].init)
self.assertTrue (the_fields[1].repr)
self.assertEqual(the_fields[2].name, 'z')
self.assertEqual(the_fields[2].type, str)
self.assertFalse(hasattr(C, 'z'))
self.assertTrue (the_fields[2].init)
self.assertFalse(the_fields[2].repr)
def test_field_order(self):
@dataclass
class B:
a: str = 'B:a'
b: str = 'B:b'
c: str = 'B:c'
@dataclass
class C(B):
b: str = 'C:b'
self.assertEqual([(f.name, f.default) for f in fields(C)],
[('a', 'B:a'),
('b', 'C:b'),
('c', 'B:c')])
@dataclass
class D(B):
c: str = 'D:c'
self.assertEqual([(f.name, f.default) for f in fields(D)],
[('a', 'B:a'),
('b', 'B:b'),
('c', 'D:c')])
@dataclass
class E(D):
a: str = 'E:a'
d: str = 'E:d'
self.assertEqual([(f.name, f.default) for f in fields(E)],
[('a', 'E:a'),
('b', 'B:b'),
('c', 'D:c'),
('d', 'E:d')])
def test_class_attrs(self):
# We only have a class attribute if a default value is
# specified, either directly or via a field with a default.
default = object()
@dataclass
class C:
x: int
y: int = field(repr=False)
z: object = default
t: int = field(default=100)
self.assertFalse(hasattr(C, 'x'))
self.assertFalse(hasattr(C, 'y'))
self.assertIs (C.z, default)
self.assertEqual(C.t, 100)
def test_disallowed_mutable_defaults(self):
# For the known types, don't allow mutable default values.
for typ, empty, non_empty in [(list, [], [1]),
(dict, {}, {0:1}),
(set, set(), set([1])),
]:
with self.subTest(typ=typ):
# Can't use a zero-length value.
with self.assertRaisesRegex(ValueError,
f'mutable default {typ} for field '
'x is not allowed'):
@dataclass
class Point:
x: typ = empty
# Nor a non-zero-length value
with self.assertRaisesRegex(ValueError,
f'mutable default {typ} for field '
'y is not allowed'):
@dataclass
class Point:
y: typ = non_empty
# Check subtypes also fail.
class Subclass(typ): pass
with self.assertRaisesRegex(ValueError,
f"mutable default .*Subclass'>"
' for field z is not allowed'
):
@dataclass
class Point:
z: typ = Subclass()
# Because this is a ClassVar, it can be mutable.
@dataclass
class C:
z: ClassVar[typ] = typ()
# Because this is a ClassVar, it can be mutable.
@dataclass
class C:
x: ClassVar[typ] = Subclass()
def test_deliberately_mutable_defaults(self):
# If a mutable default isn't in the known list of
# (list, dict, set), then it's okay.
class Mutable:
def __init__(self):
self.l = []
@dataclass
class C:
x: Mutable
# These 2 instances will share this value of x.
lst = Mutable()
o1 = C(lst)
o2 = C(lst)
self.assertEqual(o1, o2)
o1.x.l.extend([1, 2])
self.assertEqual(o1, o2)
self.assertEqual(o1.x.l, [1, 2])
self.assertIs(o1.x, o2.x)
def test_no_options(self):
# call with dataclass()
@dataclass()
class C:
x: int
self.assertEqual(C(42).x, 42)
def test_not_tuple(self):
# Make sure we can't be compared to a tuple.
@dataclass
class Point:
x: int
y: int
self.assertNotEqual(Point(1, 2), (1, 2))
# And that we can't compare to another unrelated dataclass
@dataclass
class C:
x: int
y: int
self.assertNotEqual(Point(1, 3), C(1, 3))
def test_base_has_init(self):
class B:
def __init__(self):
pass
# Make sure that declaring this class doesn't raise an error.
# The issue is that we can't override __init__ in our class,
# but it should be okay to add __init__ to us if our base has
# an __init__.
@dataclass
class C(B):
x: int = 0
def test_frozen(self):
@dataclass(frozen=True)
class C:
i: int
c = C(10)
self.assertEqual(c.i, 10)
with self.assertRaises(FrozenInstanceError):
c.i = 5
self.assertEqual(c.i, 10)
# Check that a derived class is still frozen, even if not
# marked so.
@dataclass
class D(C):
pass
d = D(20)
self.assertEqual(d.i, 20)
with self.assertRaises(FrozenInstanceError):
d.i = 5
self.assertEqual(d.i, 20)
def test_not_tuple(self):
# Test that some of the problems with namedtuple don't happen
# here.
@dataclass
class Point3D:
x: int
y: int
z: int
@dataclass
class Date:
year: int
month: int
day: int
self.assertNotEqual(Point3D(2017, 6, 3), Date(2017, 6, 3))
self.assertNotEqual(Point3D(1, 2, 3), (1, 2, 3))
# Make sure we can't unpack
with self.assertRaisesRegex(TypeError, 'is not iterable'):
x, y, z = Point3D(4, 5, 6)
# Maka sure another class with the same field names isn't
# equal.
@dataclass
class Point3Dv1:
x: int = 0
y: int = 0
z: int = 0
self.assertNotEqual(Point3D(0, 0, 0), Point3Dv1())
def test_function_annotations(self):
# Some dummy class and instance to use as a default.
class F:
pass
f = F()
def validate_class(cls):
# First, check __annotations__, even though they're not
# function annotations.
self.assertEqual(cls.__annotations__['i'], int)
self.assertEqual(cls.__annotations__['j'], str)
self.assertEqual(cls.__annotations__['k'], F)
self.assertEqual(cls.__annotations__['l'], float)
self.assertEqual(cls.__annotations__['z'], complex)
# Verify __init__.
signature = inspect.signature(cls.__init__)
# Check the return type, should be None
self.assertIs(signature.return_annotation, None)
# Check each parameter.
params = iter(signature.parameters.values())
param = next(params)
# This is testing an internal name, and probably shouldn't be tested.
self.assertEqual(param.name, 'self')
param = next(params)
self.assertEqual(param.name, 'i')
self.assertIs (param.annotation, int)
self.assertEqual(param.default, inspect.Parameter.empty)
self.assertEqual(param.kind, inspect.Parameter.POSITIONAL_OR_KEYWORD)
param = next(params)
self.assertEqual(param.name, 'j')
self.assertIs (param.annotation, str)
self.assertEqual(param.default, inspect.Parameter.empty)
self.assertEqual(param.kind, inspect.Parameter.POSITIONAL_OR_KEYWORD)
param = next(params)
self.assertEqual(param.name, 'k')
self.assertIs (param.annotation, F)
# Don't test for the default, since it's set to _MISSING
self.assertEqual(param.kind, inspect.Parameter.POSITIONAL_OR_KEYWORD)
param = next(params)
self.assertEqual(param.name, 'l')
self.assertIs (param.annotation, float)
# Don't test for the default, since it's set to _MISSING
self.assertEqual(param.kind, inspect.Parameter.POSITIONAL_OR_KEYWORD)
self.assertRaises(StopIteration, next, params)
@dataclass
class C:
i: int
j: str
k: F = f
l: float=field(default=None)
z: complex=field(default=3+4j, init=False)
validate_class(C)
# Now repeat with __hash__.
@dataclass(frozen=True, hash=True)
class C:
i: int
j: str
k: F = f
l: float=field(default=None)
z: complex=field(default=3+4j, init=False)
validate_class(C)
def test_dont_include_other_annotations(self):
@dataclass
class C:
i: int
def foo(self) -> int:
return 4
@property
def bar(self) -> int:
return 5
self.assertEqual(list(C.__annotations__), ['i'])
self.assertEqual(C(10).foo(), 4)
self.assertEqual(C(10).bar, 5)
def test_post_init(self):
# Just make sure it gets called
@dataclass
class C:
def __post_init__(self):
raise CustomError()
with self.assertRaises(CustomError):
C()
@dataclass
class C:
i: int = 10
def __post_init__(self):
if self.i == 10:
raise CustomError()
with self.assertRaises(CustomError):
C()
# post-init gets called, but doesn't raise. This is just
# checking that self is used correctly.
C(5)
# If there's not an __init__, then post-init won't get called.
@dataclass(init=False)
class C:
def __post_init__(self):
raise CustomError()
# Creating the class won't raise
C()
@dataclass
class C:
x: int = 0
def __post_init__(self):
self.x *= 2
self.assertEqual(C().x, 0)
self.assertEqual(C(2).x, 4)
# Make sure that if we'r frozen, post-init can't set
# attributes.
@dataclass(frozen=True)
class C:
x: int = 0
def __post_init__(self):
self.x *= 2
with self.assertRaises(FrozenInstanceError):
C()
def test_post_init_super(self):
# Make sure super() post-init isn't called by default.
class B:
def __post_init__(self):
raise CustomError()
@dataclass
class C(B):
def __post_init__(self):
self.x = 5
self.assertEqual(C().x, 5)
# Now call super(), and it will raise
@dataclass
class C(B):
def __post_init__(self):
super().__post_init__()
with self.assertRaises(CustomError):
C()
# Make sure post-init is called, even if not defined in our
# class.
@dataclass
class C(B):
pass
with self.assertRaises(CustomError):
C()
def test_post_init_staticmethod(self):
flag = False
@dataclass
class C:
x: int
y: int
@staticmethod
def __post_init__():
nonlocal flag
flag = True
self.assertFalse(flag)
c = C(3, 4)
self.assertEqual((c.x, c.y), (3, 4))
self.assertTrue(flag)
def test_post_init_classmethod(self):
@dataclass
class C:
flag = False
x: int
y: int
@classmethod
def __post_init__(cls):
cls.flag = True
self.assertFalse(C.flag)
c = C(3, 4)
self.assertEqual((c.x, c.y), (3, 4))
self.assertTrue(C.flag)
def test_class_var(self):
# Make sure ClassVars are ignored in __init__, __repr__, etc.
@dataclass
class C:
x: int
y: int = 10
z: ClassVar[int] = 1000
w: ClassVar[int] = 2000
t: ClassVar[int] = 3000
c = C(5)
self.assertEqual(repr(c), 'TestCase.test_class_var.<locals>.C(x=5, y=10)')
self.assertEqual(len(fields(C)), 2) # We have 2 fields
self.assertEqual(len(C.__annotations__), 5) # And 3 ClassVars
self.assertEqual(c.z, 1000)
self.assertEqual(c.w, 2000)
self.assertEqual(c.t, 3000)
C.z += 1
self.assertEqual(c.z, 1001)
c = C(20)
self.assertEqual((c.x, c.y), (20, 10))
self.assertEqual(c.z, 1001)
self.assertEqual(c.w, 2000)
self.assertEqual(c.t, 3000)
def test_class_var_no_default(self):
# If a ClassVar has no default value, it should not be set on the class.
@dataclass
class C:
x: ClassVar[int]
self.assertNotIn('x', C.__dict__)
def test_class_var_default_factory(self):
# It makes no sense for a ClassVar to have a default factory. When
# would it be called? Call it yourself, since it's class-wide.
with self.assertRaisesRegex(TypeError,
'cannot have a default factory'):
@dataclass
class C:
x: ClassVar[int] = field(default_factory=int)
self.assertNotIn('x', C.__dict__)
def test_class_var_with_default(self):
# If a ClassVar has a default value, it should be set on the class.
@dataclass
class C:
x: ClassVar[int] = 10
self.assertEqual(C.x, 10)
@dataclass
class C:
x: ClassVar[int] = field(default=10)
self.assertEqual(C.x, 10)
def test_class_var_frozen(self):
# Make sure ClassVars work even if we're frozen.
@dataclass(frozen=True)
class C:
x: int
y: int = 10
z: ClassVar[int] = 1000
w: ClassVar[int] = 2000
t: ClassVar[int] = 3000
c = C(5)
self.assertEqual(repr(C(5)), 'TestCase.test_class_var_frozen.<locals>.C(x=5, y=10)')
self.assertEqual(len(fields(C)), 2) # We have 2 fields
self.assertEqual(len(C.__annotations__), 5) # And 3 ClassVars
self.assertEqual(c.z, 1000)
self.assertEqual(c.w, 2000)
self.assertEqual(c.t, 3000)
# We can still modify the ClassVar, it's only instances that are
# frozen.
C.z += 1
self.assertEqual(c.z, 1001)
c = C(20)
self.assertEqual((c.x, c.y), (20, 10))
self.assertEqual(c.z, 1001)
self.assertEqual(c.w, 2000)
self.assertEqual(c.t, 3000)
def test_init_var_no_default(self):
# If an InitVar has no default value, it should not be set on the class.
@dataclass
class C:
x: InitVar[int]
self.assertNotIn('x', C.__dict__)
def test_init_var_default_factory(self):
# It makes no sense for an InitVar to have a default factory. When
# would it be called? Call it yourself, since it's class-wide.
with self.assertRaisesRegex(TypeError,
'cannot have a default factory'):
@dataclass
class C:
x: InitVar[int] = field(default_factory=int)
self.assertNotIn('x', C.__dict__)
def test_init_var_with_default(self):
# If an InitVar has a default value, it should be set on the class.
@dataclass
class C:
x: InitVar[int] = 10
self.assertEqual(C.x, 10)
@dataclass
class C:
x: InitVar[int] = field(default=10)
self.assertEqual(C.x, 10)
def test_init_var(self):
@dataclass
class C:
x: int = None
init_param: InitVar[int] = None
def __post_init__(self, init_param):
if self.x is None:
self.x = init_param*2
c = C(init_param=10)
self.assertEqual(c.x, 20)
def test_init_var_inheritance(self):
# Note that this deliberately tests that a dataclass need not
# have a __post_init__ function if it has an InitVar field.
# It could just be used in a derived class, as shown here.
@dataclass
class Base:
x: int
init_base: InitVar[int]
# We can instantiate by passing the InitVar, even though
# it's not used.
b = Base(0, 10)
self.assertEqual(vars(b), {'x': 0})
@dataclass
class C(Base):
y: int
init_derived: InitVar[int]
def __post_init__(self, init_base, init_derived):
self.x = self.x + init_base
self.y = self.y + init_derived
c = C(10, 11, 50, 51)
self.assertEqual(vars(c), {'x': 21, 'y': 101})
def test_default_factory(self):
# Test a factory that returns a new list.
@dataclass
class C:
x: int
y: list = field(default_factory=list)
c0 = C(3)
c1 = C(3)
self.assertEqual(c0.x, 3)
self.assertEqual(c0.y, [])
self.assertEqual(c0, c1)
self.assertIsNot(c0.y, c1.y)
self.assertEqual(astuple(C(5, [1])), (5, [1]))
# Test a factory that returns a shared list.
l = []
@dataclass
class C:
x: int
y: list = field(default_factory=lambda: l)
c0 = C(3)
c1 = C(3)
self.assertEqual(c0.x, 3)
self.assertEqual(c0.y, [])
self.assertEqual(c0, c1)
self.assertIs(c0.y, c1.y)
self.assertEqual(astuple(C(5, [1])), (5, [1]))
# Test various other field flags.
# repr
@dataclass
class C:
x: list = field(default_factory=list, repr=False)
self.assertEqual(repr(C()), 'TestCase.test_default_factory.<locals>.C()')
self.assertEqual(C().x, [])
# hash
@dataclass(hash=True)
class C:
x: list = field(default_factory=list, hash=False)
self.assertEqual(astuple(C()), ([],))
self.assertEqual(hash(C()), hash(()))
# init (see also test_default_factory_with_no_init)
@dataclass
class C:
x: list = field(default_factory=list, init=False)
self.assertEqual(astuple(C()), ([],))
# compare
@dataclass
class C:
x: list = field(default_factory=list, compare=False)
self.assertEqual(C(), C([1]))
def test_default_factory_with_no_init(self):
# We need a factory with a side effect.
factory = Mock()
@dataclass
class C:
x: list = field(default_factory=factory, init=False)
# Make sure the default factory is called for each new instance.
C().x
self.assertEqual(factory.call_count, 1)
C().x
self.assertEqual(factory.call_count, 2)
def test_default_factory_not_called_if_value_given(self):
# We need a factory that we can test if it's been called.
factory = Mock()
@dataclass
class C:
x: int = field(default_factory=factory)
# Make sure that if a field has a default factory function,
# it's not called if a value is specified.
C().x
self.assertEqual(factory.call_count, 1)
self.assertEqual(C(10).x, 10)
self.assertEqual(factory.call_count, 1)
C().x
self.assertEqual(factory.call_count, 2)
def x_test_classvar_default_factory(self):
# XXX: it's an error for a ClassVar to have a factory function
@dataclass
class C:
x: ClassVar[int] = field(default_factory=int)
self.assertIs(C().x, int)
def test_isdataclass(self):
# There is no isdataclass() helper any more, but the PEP
# describes how to write it, so make sure that works. Note
# that this version returns True for both classes and
# instances.
def isdataclass(obj):
try:
fields(obj)
return True
except TypeError:
return False
self.assertFalse(isdataclass(0))
self.assertFalse(isdataclass(int))
@dataclass
class C:
x: int
self.assertTrue(isdataclass(C))
self.assertTrue(isdataclass(C(0)))
def test_helper_fields_with_class_instance(self):
# Check that we can call fields() on either a class or instance,
# and get back the same thing.
@dataclass
class C:
x: int
y: float
self.assertEqual(fields(C), fields(C(0, 0.0)))
def test_helper_fields_exception(self):
# Check that TypeError is raised if not passed a dataclass or
# instance.
with self.assertRaisesRegex(TypeError, 'dataclass type or instance'):
fields(0)
class C: pass
with self.assertRaisesRegex(TypeError, 'dataclass type or instance'):
fields(C)
with self.assertRaisesRegex(TypeError, 'dataclass type or instance'):
fields(C())
def test_helper_asdict(self):
# Basic tests for asdict(), it should return a new dictionary
@dataclass
class C:
x: int
y: int
c = C(1, 2)
self.assertEqual(asdict(c), {'x': 1, 'y': 2})
self.assertEqual(asdict(c), asdict(c))
self.assertIsNot(asdict(c), asdict(c))
c.x = 42
self.assertEqual(asdict(c), {'x': 42, 'y': 2})
self.assertIs(type(asdict(c)), dict)
def test_helper_asdict_raises_on_classes(self):
# asdict() should raise on a class object
@dataclass
class C:
x: int
y: int
with self.assertRaisesRegex(TypeError, 'dataclass instance'):
asdict(C)
with self.assertRaisesRegex(TypeError, 'dataclass instance'):
asdict(int)
def test_helper_asdict_copy_values(self):
@dataclass
class C:
x: int
y: List[int] = field(default_factory=list)
initial = []
c = C(1, initial)
d = asdict(c)
self.assertEqual(d['y'], initial)
self.assertIsNot(d['y'], initial)
c = C(1)
d = asdict(c)
d['y'].append(1)
self.assertEqual(c.y, [])
def test_helper_asdict_nested(self):
@dataclass
class UserId:
token: int
group: int
@dataclass
class User:
name: str
id: UserId
u = User('Joe', UserId(123, 1))
d = asdict(u)
self.assertEqual(d, {'name': 'Joe', 'id': {'token': 123, 'group': 1}})
self.assertIsNot(asdict(u), asdict(u))
u.id.group = 2
self.assertEqual(asdict(u), {'name': 'Joe',
'id': {'token': 123, 'group': 2}})
def test_helper_asdict_builtin_containers(self):
@dataclass
class User:
name: str
id: int
@dataclass
class GroupList:
id: int
users: List[User]
@dataclass
class GroupTuple:
id: int
users: Tuple[User, ...]
@dataclass
class GroupDict:
id: int
users: Dict[str, User]
a = User('Alice', 1)
b = User('Bob', 2)
gl = GroupList(0, [a, b])
gt = GroupTuple(0, (a, b))
gd = GroupDict(0, {'first': a, 'second': b})
self.assertEqual(asdict(gl), {'id': 0, 'users': [{'name': 'Alice', 'id': 1},
{'name': 'Bob', 'id': 2}]})
self.assertEqual(asdict(gt), {'id': 0, 'users': ({'name': 'Alice', 'id': 1},
{'name': 'Bob', 'id': 2})})
self.assertEqual(asdict(gd), {'id': 0, 'users': {'first': {'name': 'Alice', 'id': 1},
'second': {'name': 'Bob', 'id': 2}}})
def test_helper_asdict_builtin_containers(self):
@dataclass
class Child:
d: object
@dataclass
class Parent:
child: Child
self.assertEqual(asdict(Parent(Child([1]))), {'child': {'d': [1]}})
self.assertEqual(asdict(Parent(Child({1: 2}))), {'child': {'d': {1: 2}}})
def test_helper_asdict_factory(self):
@dataclass
class C:
x: int
y: int
c = C(1, 2)
d = asdict(c, dict_factory=OrderedDict)
self.assertEqual(d, OrderedDict([('x', 1), ('y', 2)]))
self.assertIsNot(d, asdict(c, dict_factory=OrderedDict))
c.x = 42
d = asdict(c, dict_factory=OrderedDict)
self.assertEqual(d, OrderedDict([('x', 42), ('y', 2)]))
self.assertIs(type(d), OrderedDict)
def test_helper_astuple(self):
# Basic tests for astuple(), it should return a new tuple
@dataclass
class C:
x: int
y: int = 0
c = C(1)
self.assertEqual(astuple(c), (1, 0))
self.assertEqual(astuple(c), astuple(c))
self.assertIsNot(astuple(c), astuple(c))
c.y = 42
self.assertEqual(astuple(c), (1, 42))
self.assertIs(type(astuple(c)), tuple)
def test_helper_astuple_raises_on_classes(self):
# astuple() should raise on a class object
@dataclass
class C:
x: int
y: int
with self.assertRaisesRegex(TypeError, 'dataclass instance'):
astuple(C)
with self.assertRaisesRegex(TypeError, 'dataclass instance'):
astuple(int)
def test_helper_astuple_copy_values(self):
@dataclass
class C:
x: int
y: List[int] = field(default_factory=list)
initial = []
c = C(1, initial)
t = astuple(c)
self.assertEqual(t[1], initial)
self.assertIsNot(t[1], initial)
c = C(1)
t = astuple(c)
t[1].append(1)
self.assertEqual(c.y, [])
def test_helper_astuple_nested(self):
@dataclass
class UserId:
token: int
group: int
@dataclass
class User:
name: str
id: UserId
u = User('Joe', UserId(123, 1))
t = astuple(u)
self.assertEqual(t, ('Joe', (123, 1)))
self.assertIsNot(astuple(u), astuple(u))
u.id.group = 2
self.assertEqual(astuple(u), ('Joe', (123, 2)))
def test_helper_astuple_builtin_containers(self):
@dataclass
class User:
name: str
id: int
@dataclass
class GroupList:
id: int
users: List[User]
@dataclass
class GroupTuple:
id: int
users: Tuple[User, ...]
@dataclass
class GroupDict:
id: int
users: Dict[str, User]
a = User('Alice', 1)
b = User('Bob', 2)
gl = GroupList(0, [a, b])
gt = GroupTuple(0, (a, b))
gd = GroupDict(0, {'first': a, 'second': b})
self.assertEqual(astuple(gl), (0, [('Alice', 1), ('Bob', 2)]))
self.assertEqual(astuple(gt), (0, (('Alice', 1), ('Bob', 2))))
self.assertEqual(astuple(gd), (0, {'first': ('Alice', 1), 'second': ('Bob', 2)}))
def test_helper_astuple_builtin_containers(self):
@dataclass
class Child:
d: object
@dataclass
class Parent:
child: Child
self.assertEqual(astuple(Parent(Child([1]))), (([1],),))
self.assertEqual(astuple(Parent(Child({1: 2}))), (({1: 2},),))
def test_helper_astuple_factory(self):
@dataclass
class C:
x: int
y: int
NT = namedtuple('NT', 'x y')
def nt(lst):
return NT(*lst)
c = C(1, 2)
t = astuple(c, tuple_factory=nt)
self.assertEqual(t, NT(1, 2))
self.assertIsNot(t, astuple(c, tuple_factory=nt))
c.x = 42
t = astuple(c, tuple_factory=nt)
self.assertEqual(t, NT(42, 2))
self.assertIs(type(t), NT)
def test_dynamic_class_creation(self):
cls_dict = {'__annotations__': OrderedDict(x=int, y=int),
}
# Create the class.
cls = type('C', (), cls_dict)
# Make it a dataclass.
cls1 = dataclass(cls)
self.assertEqual(cls1, cls)
self.assertEqual(asdict(cls(1, 2)), {'x': 1, 'y': 2})
def test_dynamic_class_creation_using_field(self):
cls_dict = {'__annotations__': OrderedDict(x=int, y=int),
'y': field(default=5),
}
# Create the class.
cls = type('C', (), cls_dict)
# Make it a dataclass.
cls1 = dataclass(cls)
self.assertEqual(cls1, cls)
self.assertEqual(asdict(cls1(1)), {'x': 1, 'y': 5})
def test_init_in_order(self):
@dataclass
class C:
a: int
b: int = field()
c: list = field(default_factory=list, init=False)
d: list = field(default_factory=list)
e: int = field(default=4, init=False)
f: int = 4
calls = []
def setattr(self, name, value):
calls.append((name, value))
C.__setattr__ = setattr
c = C(0, 1)
self.assertEqual(('a', 0), calls[0])
self.assertEqual(('b', 1), calls[1])
self.assertEqual(('c', []), calls[2])
self.assertEqual(('d', []), calls[3])
self.assertNotIn(('e', 4), calls)
self.assertEqual(('f', 4), calls[4])
def test_items_in_dicts(self):
@dataclass
class C:
a: int
b: list = field(default_factory=list, init=False)
c: list = field(default_factory=list)
d: int = field(default=4, init=False)
e: int = 0
c = C(0)
# Class dict
self.assertNotIn('a', C.__dict__)
self.assertNotIn('b', C.__dict__)
self.assertNotIn('c', C.__dict__)
self.assertIn('d', C.__dict__)
self.assertEqual(C.d, 4)
self.assertIn('e', C.__dict__)
self.assertEqual(C.e, 0)
# Instance dict
self.assertIn('a', c.__dict__)
self.assertEqual(c.a, 0)
self.assertIn('b', c.__dict__)
self.assertEqual(c.b, [])
self.assertIn('c', c.__dict__)
self.assertEqual(c.c, [])
self.assertNotIn('d', c.__dict__)
self.assertIn('e', c.__dict__)
self.assertEqual(c.e, 0)
def test_alternate_classmethod_constructor(self):
# Since __post_init__ can't take params, use a classmethod
# alternate constructor. This is mostly an example to show how
# to use this technique.
@dataclass
class C:
x: int
@classmethod
def from_file(cls, filename):
# In a real example, create a new instance
# and populate 'x' from contents of a file.
value_in_file = 20
return cls(value_in_file)
self.assertEqual(C.from_file('filename').x, 20)
def test_field_metadata_default(self):
# Make sure the default metadata is read-only and of
# zero length.
@dataclass
class C:
i: int
self.assertFalse(fields(C)[0].metadata)
self.assertEqual(len(fields(C)[0].metadata), 0)
with self.assertRaisesRegex(TypeError,
'does not support item assignment'):
fields(C)[0].metadata['test'] = 3
def test_field_metadata_mapping(self):
# Make sure only a mapping can be passed as metadata
# zero length.
with self.assertRaises(TypeError):
@dataclass
class C:
i: int = field(metadata=0)
# Make sure an empty dict works
@dataclass
class C:
i: int = field(metadata={})
self.assertFalse(fields(C)[0].metadata)
self.assertEqual(len(fields(C)[0].metadata), 0)
with self.assertRaisesRegex(TypeError,
'does not support item assignment'):
fields(C)[0].metadata['test'] = 3
# Make sure a non-empty dict works.
@dataclass
class C:
i: int = field(metadata={'test': 10, 'bar': '42', 3: 'three'})
self.assertEqual(len(fields(C)[0].metadata), 3)
self.assertEqual(fields(C)[0].metadata['test'], 10)
self.assertEqual(fields(C)[0].metadata['bar'], '42')
self.assertEqual(fields(C)[0].metadata[3], 'three')
with self.assertRaises(KeyError):
# Non-existent key.
fields(C)[0].metadata['baz']
with self.assertRaisesRegex(TypeError,
'does not support item assignment'):
fields(C)[0].metadata['test'] = 3
def test_field_metadata_custom_mapping(self):
# Try a custom mapping.
class SimpleNameSpace:
def __init__(self, **kw):
self.__dict__.update(kw)
def __getitem__(self, item):
if item == 'xyzzy':
return 'plugh'
return getattr(self, item)
def __len__(self):
return self.__dict__.__len__()
@dataclass
class C:
i: int = field(metadata=SimpleNameSpace(a=10))
self.assertEqual(len(fields(C)[0].metadata), 1)
self.assertEqual(fields(C)[0].metadata['a'], 10)
with self.assertRaises(AttributeError):
fields(C)[0].metadata['b']
# Make sure we're still talking to our custom mapping.
self.assertEqual(fields(C)[0].metadata['xyzzy'], 'plugh')
def test_generic_dataclasses(self):
T = TypeVar('T')
@dataclass
class LabeledBox(Generic[T]):
content: T
label: str = '<unknown>'
box = LabeledBox(42)
self.assertEqual(box.content, 42)
self.assertEqual(box.label, '<unknown>')
# subscripting the resulting class should work, etc.
Alias = List[LabeledBox[int]]
def test_generic_extending(self):
S = TypeVar('S')
T = TypeVar('T')
@dataclass
class Base(Generic[T, S]):
x: T
y: S
@dataclass
class DataDerived(Base[int, T]):
new_field: str
Alias = DataDerived[str]
c = Alias(0, 'test1', 'test2')
self.assertEqual(astuple(c), (0, 'test1', 'test2'))
class NonDataDerived(Base[int, T]):
def new_method(self):
return self.y
Alias = NonDataDerived[float]
c = Alias(10, 1.0)
self.assertEqual(c.new_method(), 1.0)
def test_helper_replace(self):
@dataclass(frozen=True)
class C:
x: int
y: int
c = C(1, 2)
c1 = replace(c, x=3)
self.assertEqual(c1.x, 3)
self.assertEqual(c1.y, 2)
def test_helper_replace_frozen(self):
@dataclass(frozen=True)
class C:
x: int
y: int
z: int = field(init=False, default=10)
t: int = field(init=False, default=100)
c = C(1, 2)
c1 = replace(c, x=3)
self.assertEqual((c.x, c.y, c.z, c.t), (1, 2, 10, 100))
self.assertEqual((c1.x, c1.y, c1.z, c1.t), (3, 2, 10, 100))
with self.assertRaisesRegex(ValueError, 'init=False'):
replace(c, x=3, z=20, t=50)
with self.assertRaisesRegex(ValueError, 'init=False'):
replace(c, z=20)
replace(c, x=3, z=20, t=50)
# Make sure the result is still frozen.
with self.assertRaisesRegex(FrozenInstanceError, "cannot assign to field 'x'"):
c1.x = 3
# Make sure we can't replace an attribute that doesn't exist,
# if we're also replacing one that does exist. Test this
# here, because setting attributes on frozen instances is
# handled slightly differently from non-frozen ones.
with self.assertRaisesRegex(TypeError, "__init__\(\) got an unexpected "
"keyword argument 'a'"):
c1 = replace(c, x=20, a=5)
def test_helper_replace_invalid_field_name(self):
@dataclass(frozen=True)
class C:
x: int
y: int
c = C(1, 2)
with self.assertRaisesRegex(TypeError, "__init__\(\) got an unexpected "
"keyword argument 'z'"):
c1 = replace(c, z=3)
def test_helper_replace_invalid_object(self):
@dataclass(frozen=True)
class C:
x: int
y: int
with self.assertRaisesRegex(TypeError, 'dataclass instance'):
replace(C, x=3)
with self.assertRaisesRegex(TypeError, 'dataclass instance'):
replace(0, x=3)
def test_helper_replace_no_init(self):
@dataclass
class C:
x: int
y: int = field(init=False, default=10)
c = C(1)
c.y = 20
# Make sure y gets the default value.
c1 = replace(c, x=5)
self.assertEqual((c1.x, c1.y), (5, 10))
# Trying to replace y is an error.
with self.assertRaisesRegex(ValueError, 'init=False'):
replace(c, x=2, y=30)
with self.assertRaisesRegex(ValueError, 'init=False'):
replace(c, y=30)
def test_dataclassses_pickleable(self):
global P, Q, R
@dataclass
class P:
x: int
y: int = 0
@dataclass
class Q:
x: int
y: int = field(default=0, init=False)
@dataclass
class R:
x: int
y: List[int] = field(default_factory=list)
q = Q(1)
q.y = 2
samples = [P(1), P(1, 2), Q(1), q, R(1), R(1, [2, 3, 4])]
for sample in samples:
for proto in range(pickle.HIGHEST_PROTOCOL + 1):
with self.subTest(sample=sample, proto=proto):
new_sample = pickle.loads(pickle.dumps(sample, proto))
self.assertEqual(sample.x, new_sample.x)
self.assertEqual(sample.y, new_sample.y)
self.assertIsNot(sample, new_sample)
new_sample.x = 42
another_new_sample = pickle.loads(pickle.dumps(new_sample, proto))
self.assertEqual(new_sample.x, another_new_sample.x)
self.assertEqual(sample.y, another_new_sample.y)
def test_helper_make_dataclass(self):
C = make_dataclass('C',
[('x', int),
('y', int, field(default=5))],
namespace={'add_one': lambda self: self.x + 1})
c = C(10)
self.assertEqual((c.x, c.y), (10, 5))
self.assertEqual(c.add_one(), 11)
def test_helper_make_dataclass_no_mutate_namespace(self):
# Make sure a provided namespace isn't mutated.
ns = {}
C = make_dataclass('C',
[('x', int),
('y', int, field(default=5))],
namespace=ns)
self.assertEqual(ns, {})
def test_helper_make_dataclass_base(self):
class Base1:
pass
class Base2:
pass
C = make_dataclass('C',
[('x', int)],
bases=(Base1, Base2))
c = C(2)
self.assertIsInstance(c, C)
self.assertIsInstance(c, Base1)
self.assertIsInstance(c, Base2)
def test_helper_make_dataclass_base_dataclass(self):
@dataclass
class Base1:
x: int
class Base2:
pass
C = make_dataclass('C',
[('y', int)],
bases=(Base1, Base2))
with self.assertRaisesRegex(TypeError, 'required positional'):
c = C(2)
c = C(1, 2)
self.assertIsInstance(c, C)
self.assertIsInstance(c, Base1)
self.assertIsInstance(c, Base2)
self.assertEqual((c.x, c.y), (1, 2))
def test_helper_make_dataclass_init_var(self):
def post_init(self, y):
self.x *= y
C = make_dataclass('C',
[('x', int),
('y', InitVar[int]),
],
namespace={'__post_init__': post_init},
)
c = C(2, 3)
self.assertEqual(vars(c), {'x': 6})
self.assertEqual(len(fields(c)), 1)
def test_helper_make_dataclass_class_var(self):
C = make_dataclass('C',
[('x', int),
('y', ClassVar[int], 10),
('z', ClassVar[int], field(default=20)),
])
c = C(1)
self.assertEqual(vars(c), {'x': 1})
self.assertEqual(len(fields(c)), 1)
self.assertEqual(C.y, 10)
self.assertEqual(C.z, 20)
class TestDocString(unittest.TestCase):
def assertDocStrEqual(self, a, b):
# Because 3.6 and 3.7 differ in how inspect.signature work
# (see bpo #32108), for the time being just compare them with
# whitespace stripped.
self.assertEqual(a.replace(' ', ''), b.replace(' ', ''))
def test_existing_docstring_not_overridden(self):
@dataclass
class C:
"""Lorem ipsum"""
x: int
self.assertEqual(C.__doc__, "Lorem ipsum")
def test_docstring_no_fields(self):
@dataclass
class C:
pass
self.assertDocStrEqual(C.__doc__, "C()")
def test_docstring_one_field(self):
@dataclass
class C:
x: int
self.assertDocStrEqual(C.__doc__, "C(x:int)")
def test_docstring_two_fields(self):
@dataclass
class C:
x: int
y: int
self.assertDocStrEqual(C.__doc__, "C(x:int, y:int)")
def test_docstring_three_fields(self):
@dataclass
class C:
x: int
y: int
z: str
self.assertDocStrEqual(C.__doc__, "C(x:int, y:int, z:str)")
def test_docstring_one_field_with_default(self):
@dataclass
class C:
x: int = 3
self.assertDocStrEqual(C.__doc__, "C(x:int=3)")
def test_docstring_one_field_with_default_none(self):
@dataclass
class C:
x: Union[int, type(None)] = None
self.assertDocStrEqual(C.__doc__, "C(x:Union[int, NoneType]=None)")
def test_docstring_list_field(self):
@dataclass
class C:
x: List[int]
self.assertDocStrEqual(C.__doc__, "C(x:List[int])")
def test_docstring_list_field_with_default_factory(self):
@dataclass
class C:
x: List[int] = field(default_factory=list)
self.assertDocStrEqual(C.__doc__, "C(x:List[int]=<factory>)")
def test_docstring_deque_field(self):
@dataclass
class C:
x: deque
self.assertDocStrEqual(C.__doc__, "C(x:collections.deque)")
def test_docstring_deque_field_with_default_factory(self):
@dataclass
class C:
x: deque = field(default_factory=deque)
self.assertDocStrEqual(C.__doc__, "C(x:collections.deque=<factory>)")
if __name__ == '__main__':
unittest.main()
