Python pydantic.Field() Examples

def test_default_factory_called_once():
    """It should call only once the given factory by default"""

    class Seq:
        def __init__(self):
            self.v = 0

        def __call__(self):
            self.v += 1
            return self.v

    class MyModel(BaseModel):
        id: int = Field(default_factory=Seq())

    m1 = MyModel()
    assert m1.id == 1
    m2 = MyModel()
    assert m2.id == 2
    assert m1.id == 1 

def test_del(self):
        class Foo(CCIDictModel):
            bar: str = None
            fields_ = Field([], alias="fields")

        x = Foo.parse_obj({"bar": "q"})
        assert x["bar"] == x.bar == "q"
        assert "bar" in x
        del x["bar"]
        assert "bar" not in x
        assert x.get("bar") is None

        assert x["fields"] == x.fields == []
        assert "fields" in x
        del x["fields"]
        assert "fields" not in x
        assert x.get("fields") is None 

def test_forward_ref_with_field(create_module):
    create_module(
        """
from typing import List
from pydantic import BaseModel, Field
from pydantic.typing import ForwardRef

Foo = ForwardRef('Foo')

try:
    class Foo(BaseModel):
        c: List[Foo] = Field(..., gt=0)
except ValueError:
    pass
else:
    raise AssertionError('error not raised')
    """
    ) 

def test_default_factory_called_once_2():
    """It should call only once the given factory by default"""

    v = 0

    def factory():
        nonlocal v
        v += 1
        return v

    class MyModel(BaseModel):
        id: int = Field(default_factory=factory)

    m1 = MyModel()
    assert m1.id == 1
    m2 = MyModel()
    assert m2.id == 2 

def test_custom_init_signature():
    class MyModel(BaseModel):
        id: int
        name: str = 'John Doe'
        f__: str = Field(..., alias='foo')

        class Config:
            extra = Extra.allow

        def __init__(self, id: int = 1, bar=2, *, baz: Any, **data):
            super().__init__(id=id, **data)
            self.bar = bar
            self.baz = baz

    sig = signature(MyModel)
    assert _equals(
        map(str, sig.parameters.values()),
        ('id: int = 1', 'bar=2', 'baz: Any', "name: str = 'John Doe'", 'foo: str', '**data'),
    )

    assert _equals(str(sig), "(id: int = 1, bar=2, *, baz: Any, name: str = 'John Doe', foo: str, **data) -> None") 

def test_schema_class():
    class Model(BaseModel):
        foo: int = Field(4, title='Foo is Great')
        bar: str = Field(..., description='this description of bar')

    with pytest.raises(ValidationError):
        Model()

    m = Model(bar=123)
    assert m.dict() == {'foo': 4, 'bar': '123'}

    assert Model.schema() == {
        'type': 'object',
        'title': 'Model',
        'properties': {
            'foo': {'type': 'integer', 'title': 'Foo is Great', 'default': 4},
            'bar': {'type': 'string', 'title': 'Bar', 'description': 'this description of bar'},
        },
        'required': ['bar'],
    } 

def test_env_inheritance_field(env):
    class SettingsParent(BaseSettings):
        foobar: str = Field('parent default', env='foobar_env')

    class SettingsChild(SettingsParent):
        foobar: str = 'child default'

    assert SettingsParent().foobar == 'parent default'
    assert SettingsParent(foobar='abc').foobar == 'abc'

    assert SettingsChild().foobar == 'child default'
    assert SettingsChild(foobar='abc').foobar == 'abc'
    env.set('foobar_env', 'env value')
    assert SettingsParent().foobar == 'env value'
    assert SettingsParent(foobar='abc').foobar == 'abc'
    assert SettingsChild().foobar == 'child default'
    assert SettingsChild(foobar='abc').foobar == 'abc' 

def test_const_str():
    class Model(BaseModel):
        a: str = Field('some string', const=True)

    assert Model.schema() == {
        'title': 'Model',
        'type': 'object',
        'properties': {'a': {'title': 'A', 'type': 'string', 'const': 'some string'}},
    } 

def test_dict_with_extra_keys():
    class MyModel(BaseModel):
        a: str = Field(None, alias='alias_a')

        class Config:
            extra = Extra.allow

    m = MyModel(extra_key='extra')
    assert m.dict() == {'a': None, 'extra_key': 'extra'}
    assert m.dict(by_alias=True) == {'alias_a': None, 'extra_key': 'extra'} 

def test_two_defaults():
    with pytest.raises(ValueError, match='^cannot specify both default and default_factory$'):

        class Model(BaseModel):
            a: int = Field(default=3, default_factory=lambda: 3) 

def test_none_min_max_items():
    # None default
    class Foo(BaseModel):
        foo: List = Field(None)
        bar: List = Field(None, min_items=0)
        baz: List = Field(None, max_items=10)

    f1 = Foo()
    f2 = Foo(bar=None)
    f3 = Foo(baz=None)
    f4 = Foo(bar=None, baz=None)
    for f in (f1, f2, f3, f4):
        assert f.foo is None
        assert f.bar is None
        assert f.baz is None 

def test_reuse_same_field():
    required_field = Field(...)

    class Model1(BaseModel):
        required: str = required_field

    class Model2(BaseModel):
        required: str = required_field

    with pytest.raises(ValidationError):
        Model1.parse_obj({})
    with pytest.raises(ValidationError):
        Model2.parse_obj({}) 

def test_schema_class_by_alias():
    class Model(BaseModel):
        foo: int = Field(4, alias='foofoo')

    assert list(Model.schema()['properties'].keys()) == ['foofoo']
    assert list(Model.schema(by_alias=False)['properties'].keys()) == ['foo'] 

def test_choices():
    FooEnum = Enum('FooEnum', {'foo': 'f', 'bar': 'b'})
    BarEnum = IntEnum('BarEnum', {'foo': 1, 'bar': 2})

    class SpamEnum(str, Enum):
        foo = 'f'
        bar = 'b'

    class Model(BaseModel):
        foo: FooEnum
        bar: BarEnum
        spam: SpamEnum = Field(None)

    assert Model.schema() == {
        'title': 'Model',
        'type': 'object',
        'properties': {
            'foo': {'$ref': '#/definitions/FooEnum'},
            'bar': {'$ref': '#/definitions/BarEnum'},
            'spam': {'$ref': '#/definitions/SpamEnum'},
        },
        'required': ['foo', 'bar'],
        'definitions': {
            'FooEnum': {'title': 'FooEnum', 'description': 'An enumeration.', 'enum': ['f', 'b']},
            'BarEnum': {'title': 'BarEnum', 'description': 'An enumeration.', 'type': 'integer', 'enum': [1, 2]},
            'SpamEnum': {'title': 'SpamEnum', 'description': 'An enumeration.', 'type': 'string', 'enum': ['f', 'b']},
        },
    } 

def test_enum_modify_schema():
    class SpamEnum(str, Enum):
        foo = 'f'
        bar = 'b'

        @classmethod
        def __modify_schema__(cls, field_schema):
            field_schema['tsEnumNames'] = [e.name for e in cls]

    class Model(BaseModel):
        spam: SpamEnum = Field(None)

    assert Model.schema() == {
        'definitions': {
            'SpamEnum': {
                'description': 'An enumeration.',
                'enum': ['f', 'b'],
                'title': 'SpamEnum',
                'tsEnumNames': ['foo', 'bar'],
                'type': 'string',
            }
        },
        'properties': {'spam': {'$ref': '#/definitions/SpamEnum'}},
        'title': 'Model',
        'type': 'object',
    } 

def test_const_validation_json_serializable():
    class SubForm(BaseModel):
        field: int

    class Form(BaseModel):
        field1: SubForm = Field({'field': 2}, const=True)
        field2: List[SubForm] = Field([{'field': 2}], const=True)

    with pytest.raises(ValidationError) as exc_info:
        # Fails
        Form(field1={'field': 1}, field2=[{'field': 1}])

    # This should not raise an Json error
    exc_info.value.json() 

def test_const_false():
    class Model(BaseModel):
        a: str = Field('some string', const=False)

    assert Model.schema() == {
        'title': 'Model',
        'type': 'object',
        'properties': {'a': {'title': 'A', 'type': 'string', 'default': 'some string'}},
    } 

def test_constraints_schema(kwargs, type_, expected_extra):
    class Foo(BaseModel):
        a: type_ = Field('foo', title='A title', description='A description', **kwargs)

    expected_schema = {
        'title': 'Foo',
        'type': 'object',
        'properties': {'a': {'title': 'A title', 'description': 'A description', 'default': 'foo'}},
    }

    expected_schema['properties']['a'].update(expected_extra)
    assert Foo.schema() == expected_schema 

def test_unenforced_constraints_schema(kwargs, type_):
    with pytest.raises(ValueError, match='On field "a" the following field constraints are set but not enforced'):

        class Foo(BaseModel):
            a: type_ = Field('foo', title='A title', description='A description', **kwargs) 

def test_constraints_schema_validation(kwargs, type_, value):
    class Foo(BaseModel):
        a: type_ = Field('foo', title='A title', description='A description', **kwargs)

    assert Foo(a=value) 

def test_constraints_schema_validation_raises(kwargs, type_, value):
    class Foo(BaseModel):
        a: type_ = Field('foo', title='A title', description='A description', **kwargs)

    with pytest.raises(ValidationError):
        Foo(a=value) 

def test_schema_kwargs():
    class Foo(BaseModel):
        a: str = Field('foo', examples=['bar'])

    assert Foo.schema() == {
        'title': 'Foo',
        'type': 'object',
        'properties': {'a': {'type': 'string', 'title': 'A', 'default': 'foo', 'examples': ['bar']}},
    } 

def test_real_vs_phony_constraints():
    class Model1(BaseModel):
        foo: int = Field(..., gt=123)

        class Config:
            title = 'Test Model'

    class Model2(BaseModel):
        foo: int = Field(..., exclusiveMinimum=123)

        class Config:
            title = 'Test Model'

    with pytest.raises(ValidationError, match='ensure this value is greater than 123'):
        Model1(foo=122)

    assert Model2(foo=122).dict() == {'foo': 122}

    assert (
        Model1.schema()
        == Model2.schema()
        == {
            'title': 'Test Model',
            'type': 'object',
            'properties': {'foo': {'title': 'Foo', 'exclusiveMinimum': 123, 'type': 'integer'}},
            'required': ['foo'],
        }
    ) 

def test_env_field(env):
    with pytest.raises(TypeError, match=r'invalid field env: 123 \(int\); should be string, list or set'):

        class Settings(BaseSettings):
            foobar: str = Field(..., env=123) 

def test_fields_items(self):
        class Foo(CCIDictModel):
            bar: str = None
            fields_ = Field([], alias="fields")

        class Document(CCIDictModel):
            __root__: Foo

        # JSON is YAML. Strange but true.
        foo = Document.parse_from_yaml(StringIO("{bar: 'blah'}"))
        assert type(foo) == Foo
        assert foo["fields"] == []

        foo = Document.parse_from_yaml(StringIO("{bar: 'blah', fields: [1,2]}"))
        assert foo["fields"] == [1, 2]

        foo["fields"] = ["a", "b"]
        assert foo["fields"] == ["a", "b"] 

def test_getitem_missing(self):
        class Foo(CCIDictModel):
            bar: str = None
            fields_ = Field([], alias="fields")

        x = Foo.parse_obj({})
        assert x
        with pytest.raises(IndexError):
            x["foo"]

        assert "bar" in x
        assert "fields" in x
        assert x["fields"] == [] 

def test_get(self):
        class Foo(CCIDictModel):
            bar: str = None
            fields_ = Field([], alias="fields")

        x = Foo.parse_obj({"bar": "q"})
        assert x.get("bar") == x.bar == x["bar"] == "q"
        assert x.get("xyzzy", 0) == 0
        assert x.get("xyzzy") is None
        assert x.get("fields") == [] 

def test_custom_schema():
    T = TypeVar('T')

    class MyModel(GenericModel, Generic[T]):
        a: int = Field(1, description='Custom')

    schema = MyModel[int].schema()
    assert schema['properties']['a'].get('description') == 'Custom' 

def test_model_signature():
    class Model(BaseModel):
        a: float = Field(..., title='A')
        b = Field(10)

    sig = signature(Model)
    assert sig != signature(BaseModel)
    assert _equals(map(str, sig.parameters.values()), ('a: float', 'b: int = 10'))
    assert _equals(str(sig), '(*, a: float, b: int = 10) -> None') 

def test_invalid_identifiers_signature():
    model = create_model(
        'Model', **{'123 invalid identifier!': Field(123, alias='valid_identifier'), '!': Field(0, alias='yeah')}
    )
    assert _equals(str(signature(model)), '(*, valid_identifier: int = 123, yeah: int = 0) -> None')
    model = create_model('Model', **{'123 invalid identifier!': 123, '!': Field(0, alias='yeah')})
    assert _equals(str(signature(model)), '(*, yeah: int = 0, **extra_data: Any) -> None')