Class methods can now be discovered as tests (#10552)

Fix #10525

AUTHORS

@@ -225,6 +225,7 @@ Marcin Bachry
 Marco Gorelli
 Mark Abramowitz
 Mark Dickinson
+Marko Pacak
 Markus Unterwaditzer
 Martijn Faassen
 Martin Altmayer

changelog/10525.feature.rst

@@ -0,0 +1 @@
+Test methods decorated with ``@classmethod`` can now be discovered as tests, following the same rules as normal methods. This fills the gap that static methods were discoverable as tests but not class methods.

doc/en/explanation/goodpractices.rst

@@ -50,8 +50,8 @@ Conventions for Python test discovery
 * In those directories, search for ``test_*.py`` or ``*_test.py`` files, imported by their `test package name`_.
 * From those files, collect test items:
 
-  * ``test`` prefixed test functions or methods outside of class
-  * ``test`` prefixed test functions or methods inside ``Test`` prefixed test classes (without an ``__init__`` method)
+  * ``test`` prefixed test functions or methods outside of class.
+  * ``test`` prefixed test functions or methods inside ``Test`` prefixed test classes (without an ``__init__`` method). Methods decorated with ``@staticmethod`` and ``@classmethods`` are also considered.
 
 For examples of how to customize your test discovery :doc:`/example/pythoncollection`.
 

src/_pytest/python.py

@@ -403,8 +403,8 @@ class PyCollector(PyobjMixin, nodes.Collector):
 
     def istestfunction(self, obj: object, name: str) -> bool:
         if self.funcnamefilter(name) or self.isnosetest(obj):
-            if isinstance(obj, staticmethod):
-                # staticmethods need to be unwrapped.
+            if isinstance(obj, (staticmethod, classmethod)):
+                # staticmethods and classmethods need to be unwrapped.
                 obj = safe_getattr(obj, "__func__", False)
             return callable(obj) and fixtures.getfixturemarker(obj) is None
         else:

testing/python/integration.py

@@ -416,7 +416,7 @@ def test_function_instance(pytester: Pytester) -> None:
             def test_static(): pass
         """
     )
-    assert len(items) == 3
+    assert len(items) == 4
     assert isinstance(items[0], Function)
     assert items[0].name == "test_func"
     assert items[0].instance is None
@@ -424,6 +424,6 @@ def test_function_instance(pytester: Pytester) -> None:
     assert items[1].name == "test_method"
     assert items[1].instance is not None
     assert items[1].instance.__class__.__name__ == "TestIt"
-    assert isinstance(items[2], Function)
-    assert items[2].name == "test_static"
-    assert items[2].instance is None
+    assert isinstance(items[3], Function)
+    assert items[3].name == "test_static"
+    assert items[3].instance is None

testing/test_collection.py

@@ -735,6 +735,20 @@ class Test_genitems:
         assert s.endswith("test_example_items1.testone")
         print(s)
 
+    def test_classmethod_is_discovered(self, pytester: Pytester) -> None:
+        """Test that classmethods are discovered"""
+        p = pytester.makepyfile(
+            """
+            class TestCase:
+                @classmethod
+                def test_classmethod(cls) -> None:
+                    pass
+            """
+        )
+        items, reprec = pytester.inline_genitems(p)
+        ids = [x.getmodpath() for x in items]  # type: ignore[attr-defined]
+        assert ids == ["TestCase.test_classmethod"]
+
     def test_class_and_functions_discovery_using_glob(self, pytester: Pytester) -> None:
         """Test that Python_classes and Python_functions config options work
         as prefixes and glob-like patterns (#600)."""