Merge pull request #11677 from bluetech/nodes-abc

nodes,python: mark abstract node classes as ABCs

src/_pytest/fixtures.py

@@ -135,7 +135,9 @@ def get_scope_node(
     import _pytest.python
 
     if scope is Scope.Function:
-        return node.getparent(nodes.Item)
+        # Type ignored because this is actually safe, see:
+        # https://github.com/python/mypy/issues/4717
+        return node.getparent(nodes.Item)  # type: ignore[type-abstract]
     elif scope is Scope.Class:
         return node.getparent(_pytest.python.Class)
     elif scope is Scope.Module:

src/_pytest/nodes.py

@@ -1,3 +1,4 @@
+import abc
 import os
 import warnings
 from functools import cached_property
@@ -121,7 +122,7 @@ def _imply_path(
 _NodeType = TypeVar("_NodeType", bound="Node")
 
 
-class NodeMeta(type):
+class NodeMeta(abc.ABCMeta):
     """Metaclass used by :class:`Node` to enforce that direct construction raises
     :class:`Failed`.
 
@@ -165,7 +166,7 @@ class NodeMeta(type):
             return super().__call__(*k, **known_kw)
 
 
-class Node(metaclass=NodeMeta):
+class Node(abc.ABC, metaclass=NodeMeta):
     r"""Base class of :class:`Collector` and :class:`Item`, the components of
     the test collection tree.
 
@@ -534,7 +535,7 @@ def get_fslocation_from_item(node: "Node") -> Tuple[Union[str, Path], Optional[i
     return getattr(node, "fspath", "unknown location"), -1
 
 
-class Collector(Node):
+class Collector(Node, abc.ABC):
     """Base class of all collectors.
 
     Collector create children through `collect()` and thus iteratively build
@@ -544,6 +545,7 @@ class Collector(Node):
     class CollectError(Exception):
         """An error during collection, contains a custom message."""
 
+    @abc.abstractmethod
     def collect(self) -> Iterable[Union["Item", "Collector"]]:
         """Collect children (items and collectors) for this collector."""
         raise NotImplementedError("abstract")
@@ -588,7 +590,7 @@ def _check_initialpaths_for_relpath(session: "Session", path: Path) -> Optional[
     return None
 
 
-class FSCollector(Collector):
+class FSCollector(Collector, abc.ABC):
     """Base class for filesystem collectors."""
 
     def __init__(
@@ -666,14 +668,14 @@ class FSCollector(Collector):
         return self.session.isinitpath(path)
 
 
-class File(FSCollector):
+class File(FSCollector, abc.ABC):
     """Base class for collecting tests from a file.
 
     :ref:`non-python tests`.
     """
 
 
-class Item(Node):
+class Item(Node, abc.ABC):
     """Base class of all test invocation items.
 
     Note that for a single function there might be multiple test invocation items.
@@ -739,6 +741,7 @@ class Item(Node):
                 PytestWarning,
             )
 
+    @abc.abstractmethod
     def runtest(self) -> None:
         """Run the test case for this item.
 

src/_pytest/python.py

@@ -1,4 +1,5 @@
 """Python test discovery, setup and run of test functions."""
+import abc
 import dataclasses
 import enum
 import fnmatch
@@ -380,7 +381,7 @@ del _EmptyClass
 # fmt: on
 
 
-class PyCollector(PyobjMixin, nodes.Collector):
+class PyCollector(PyobjMixin, nodes.Collector, abc.ABC):
     def funcnamefilter(self, name: str) -> bool:
         return self._matches_prefix_or_glob_option("python_functions", name)