test-data/unit/pythoneval-enum.test

-- Test cases for type checking mypy programs using full stubs and running
-- using CPython.
--
-- These are mostly regression tests -- no attempt is made to make these
-- complete.
--
-- This test file checks Enum

[case testEnumBasics]
from enum import Enum
class Medal(Enum):
    gold = 1
    silver = 2
    bronze = 3
m = Medal.gold
m = 1
[out]
_program.py:7: error: Incompatible types in assignment (expression has type "int", variable has type "Medal")

[case testEnumNameAndValue]
from enum import Enum
class Truth(Enum):
    true = True
    false = False
x = ''
x = Truth.true.name
print(Truth.true.name)
print(Truth.false.value)
[out]
true
False

[case testEnumUnique]
import enum
@enum.unique
class E(enum.Enum):
    x = 1
    y = 1  # NOTE: This duplicate value is not detected by mypy at the moment
x = 1
x = E.x
[out]
_program.py:7: error: Incompatible types in assignment (expression has type "E", variable has type "int")

[case testIntEnum_assignToIntVariable]
from enum import IntEnum
class N(IntEnum):
    x = 1
    y = 1
n = 1
n = N.x  # Subclass of int, so it's okay
s = ''
s = N.y
[out]
_program.py:8: error: Incompatible types in assignment (expression has type "N", variable has type "str")

[case testIntEnum_functionTakingIntEnum]
from enum import IntEnum
class SomeIntEnum(IntEnum):
    x = 1
def takes_some_int_enum(n: SomeIntEnum):
    pass
takes_some_int_enum(SomeIntEnum.x)
takes_some_int_enum(1)  # Error
takes_some_int_enum(SomeIntEnum(1))  # How to deal with the above
[out]
_program.py:7: error: Argument 1 to "takes_some_int_enum" has incompatible type "int"; expected "SomeIntEnum"

[case testIntEnum_functionTakingInt]
from enum import IntEnum
class SomeIntEnum(IntEnum):
    x = 1
def takes_int(i: int):
    pass
takes_int(SomeIntEnum.x)
takes_int(2)

[case testIntEnum_functionReturningIntEnum]
from enum import IntEnum
class SomeIntEnum(IntEnum):
    x = 1
def returns_some_int_enum() -> SomeIntEnum:
    return SomeIntEnum.x
an_int = 1
an_int = returns_some_int_enum()

an_enum = SomeIntEnum.x
an_enum = returns_some_int_enum()
[out]

[case testEnumMethods]
from enum import Enum

class Color(Enum):
    red = 1
    green = 2

    def m(self, x: int): pass
    @staticmethod
    def m2(x: int): pass

Color.red.m('')
Color.m2('')
[out]
_program.py:11: error: Argument 1 to "m" of "Color" has incompatible type "str"; expected "int"
_program.py:12: error: Argument 1 to "m2" of "Color" has incompatible type "str"; expected "int"

[case testIntEnum_ExtendedIntEnum_functionTakingExtendedIntEnum]
from enum import IntEnum
class ExtendedIntEnum(IntEnum):
    pass
class SomeExtIntEnum(ExtendedIntEnum):
    x = 1

def takes_int(i: int):
    pass
takes_int(SomeExtIntEnum.x)

def takes_some_ext_int_enum(s: SomeExtIntEnum):
    pass
takes_some_ext_int_enum(SomeExtIntEnum.x)


[case testNamedTupleEnum]
from typing import NamedTuple
from enum import Enum

N = NamedTuple('N', [('bar', int)])

class E(N, Enum):
    X = N(1)

def f(x: E) -> None: pass

f(E.X)