from dataclasses import dataclass, fields, field
from typing import Optional
import pytest
from dacite.dataclasses import get_default_value_for_field, create_instance, DefaultValueNotFoundError
def test_get_default_value_for_field_with_default_value():
@dataclass
class X:
i: int = 1
value = get_default_value_for_field(field=fields(X)[0])
assert value == 1
def test_get_default_value_for_field_with_default_factory():
@dataclass
class X:
i: int = field(default_factory=lambda: 1)
value = get_default_value_for_field(field=fields(X)[0])
assert value == 1
def test_get_default_value_for_optional_field():
@dataclass
class X:
i: Optional[int]
value = get_default_value_for_field(field=fields(X)[0])
assert value is None
def test_get_default_value_for_field_without_default_value():
@dataclass
class X:
i: int
with pytest.raises(DefaultValueNotFoundError):
get_default_value_for_field(field=fields(X)[0])
def test_create_instance_with_simple_data_class():
@dataclass
class X:
i: int
instance = create_instance(data_class=X, init_values={"i": 1}, post_init_values={})
assert instance == X(i=1)
def test_create_instance_with_post_init_values():
@dataclass
class X:
i: int
j: int = field(init=False)
instance = create_instance(data_class=X, init_values={"i": 1}, post_init_values={"j": 2})
assert instance.i == 1
assert instance.j == 2
