callable_marker: add type hints

Signed-off-by: Gaëtan Lehmann <[email protected]>

Author: glehmann

lib/common.py

@@ -7,7 +7,7 @@
 import time
 import traceback
 from enum import Enum
-from typing import Dict, Literal, Optional, overload, TYPE_CHECKING, Union
+from typing import Callable, cast, Dict, Literal, Optional, overload, TYPE_CHECKING, TypeVar, Union
 from uuid import UUID
 
 import pytest
@@ -17,6 +17,8 @@
 if TYPE_CHECKING:
     import lib.host
 
+T = TypeVar("T")
+
 class PackageManagerEnum(Enum):
     UNKNOWN = 1
     RPM = 2
@@ -67,7 +69,7 @@ def expand_scope_relative_nodeid(scoped_nodeid, scope, ref_nodeid):
     logging.debug("scope: %r base: %r relative: %r", scope, base, scoped_nodeid)
     return "::".join(itertools.chain(base, (scoped_nodeid,)))
 
-def callable_marker(value, request):
+def callable_marker(value: Union[T, Callable[..., T]], request: pytest.FixtureRequest) -> T:
     """
     Process value optionally generated by fixture-dependent callable.
 
@@ -83,8 +85,12 @@ def callable_marker(value, request):
                       for arg_name in inspect.getfullargspec(value).args}
         except pytest.FixtureLookupError as e:
             raise RuntimeError("fixture in mapping not found on test") from e
-        value = value(**params)
-    return value
+        # callable ensures the value is of type Callable[..., object], which is not enough in that case
+        # we can trust the static checker though, and thus use cast
+        fn = cast(Callable[..., T], value)
+        return fn(**params)
+    else:
+        return value
 
 def wait_for(fn, msg=None, timeout_secs=2 * 60, retry_delay_secs=2, invert=False):
     if msg is not None: