pytest: typecheck with pyrefly

[Tpt]

Helps to ensure the generated type stubs are compatible with it

[Tpt]

needed to make sure that IterAwaitable is a Generator

[davidhewitt]

Why does pyrefly require that?

[Tpt]

Pyrefly requires that await is called on an Awaitable that is defined in typeshed as:

@runtime_checkable
class Awaitable(Protocol[_T_co]):
    @abstractmethod
    def __await__(self) -> Generator[Any, Any, _T_co]: ...

so, because IterAwaitable.__await__ returns IterAwaitable then IterAwaitable must be a Generator that is defined as:

@runtime_checkable
class Generator(Iterator[_YieldT_co], Protocol[_YieldT_co, _SendT_contra, _ReturnT_co]):
    def __next__(self) -> _YieldT_co: ...
    @abstractmethod
    def send(self, value: _SendT_contra, /) -> _YieldT_co: ...
    @overload
    @abstractmethod
    def throw(
        self, typ: type[BaseException], val: BaseException | object = None, tb: TracebackType | None = None, /
    ) -> _YieldT_co: ...
    @overload
    @abstractmethod
    def throw(self, typ: BaseException, val: None = None, tb: TracebackType | None = None, /) -> _YieldT_co: ...
    if sys.version_info >= (3, 13):
        def close(self) -> _ReturnT_co | None: ...
    else:
        def close(self) -> None: ...

    def __iter__(self) -> Generator[_YieldT_co, _SendT_contra, _ReturnT_co]: ...

Hence the need for send, throw and close methods.