from __future__ import annotations
from dataclasses import dataclass
from typing import Optional

from src.megasniff import SchemaInflatorGenerator


def test_basic_constructor():
    class A:
        def __init__(self, a: int):
            self.a = a

    infl = SchemaInflatorGenerator()
    fn = infl.schema_to_generator(A)
    a = fn({'a': 42})

    assert a.a == 42


@dataclass
class CircA:
    b: CircB


@dataclass
class CircB:
    a: CircA | None


def test_circular():
    infl = SchemaInflatorGenerator()
    fn = infl.schema_to_generator(CircA)
    a = fn({'b': {'a': None}})

    return isinstance(a.b, CircB)


def test_optional():
    @dataclass
    class C:
        a: Optional[int] = None

    infl = SchemaInflatorGenerator()
    fn = infl.schema_to_generator(C)
    c = fn({})
    assert c.a is None