Fix mypy 2.3.0 type errors in the test suite

mypy 2.3.0 (released 2026-07-13) is stricter and surfaces 7 errors in the test
suite on unmodified main (CI's `mypy<3,>=2.1` floats to it), failing the Lint
job on every open PR. All test-only, no behavioural change.

- tests/utils/assert_equal_awaitables_or_values.py: the awaitable branch
  returns a coroutine where the declared TypeVar `T` is expected; cast it (the
  function returns an awaitable iff its inputs are awaitables).
- tests/execution/test_abstract.py: the conditionally-defined `is_type_of` and
  `type_error` (sync vs async variants) now must have identical signatures;
  pre-declare each with an explicit `Callable[..., Any]`.
- tests/execution/test_stream.py: `name` is assigned either a coroutine
  (`throw()`) or a `str`; annotate it `Any`.
- tests/execution/test_middleware.py: the awaited `subscribe(...)` item is
  inferred as `object`; cast it to `ExecutionResult` before reading `.data`.

mypy src tests, ruff check src tests and ruff format --check src tests are all
clean under the pinned tool versions (mypy 2.3.0, ruff 0.15.21).

Author: ben-xo

tests/execution/test_abstract.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import Any, NamedTuple
+from typing import TYPE_CHECKING, Any, NamedTuple
 
 import pytest
 
@@ -19,6 +19,9 @@
 )
 from graphql.utilities import build_schema
 
+if TYPE_CHECKING:
+    from collections.abc import Callable
+
 
 def sync_and_async(spec):
     """Decorator for running a test synchronously and asynchronously."""
@@ -51,6 +54,7 @@ async def execute_query(
 
 def get_is_type_of(type_, sync=True):
     """Get a sync or async is_type_of function for the given type."""
+    is_type_of: Callable[[Any, Any], Any]
     if sync:
 
         def is_type_of(obj, _info):
@@ -67,6 +71,7 @@ async def is_type_of(obj, _info):
 def get_type_error(sync=True):
     """Get a sync or async is_type_of or type resolver function that raises an error."""
     error = RuntimeError("We are testing this error")
+    type_error: Callable[..., Any]
     if sync:
 
         def type_error(*_args):

tests/execution/test_middleware.py

@@ -4,7 +4,13 @@
 
 import pytest
 
-from graphql.execution import Middleware, MiddlewareManager, execute, subscribe
+from graphql.execution import (
+    ExecutionResult,
+    Middleware,
+    MiddlewareManager,
+    execute,
+    subscribe,
+)
 from graphql.language.parser import parse
 from graphql.type import GraphQLField, GraphQLObjectType, GraphQLSchema, GraphQLString
 
@@ -262,9 +268,9 @@ async def reverse_middleware(next_, value, info, **kwargs):
                 middleware=MiddlewareManager(reverse_middleware),
             )
             assert inspect.isasyncgen(agen)
-            data = (await agen.__anext__()).data
+            data = cast("ExecutionResult", await agen.__anext__()).data
             assert data == {"bar": "rab"}
-            data = (await agen.__anext__()).data
+            data = cast("ExecutionResult", await agen.__anext__()).data
             assert data == {"bar": "foo"}
 
     def describe_without_manager():

tests/execution/test_stream.py

@@ -1691,6 +1691,7 @@ def __aiter__(self):
             async def __anext__(self):
                 count = self.count
                 self.count += 1
+                name: Any
                 if count == 1:
                     name = throw()
                 else:
@@ -1757,6 +1758,7 @@ async def __anext__(self):
                     raise StopAsyncIteration  # pragma: no cover
                 count = self.count
                 self.count += 1
+                name: Any
                 if count == 1:
                     name = throw()
                 else:

tests/utils/assert_equal_awaitables_or_values.py

@@ -23,7 +23,7 @@ def assert_equal_awaitables_or_values(*items: T) -> T:
         async def assert_matching_awaitables():
             return assert_matching_values(*(await asyncio.gather(*awaitable_items)))
 
-        return assert_matching_awaitables()
+        return cast("T", assert_matching_awaitables())
 
     if all(not is_awaitable(item) for item in items):
         return assert_matching_values(*items)