Add discover_imports in conf, don't collect imported classes named Test* closes #12749`

AUTHORS

@@ -400,6 +400,7 @@ Stefanie Molin
 Stefano Taschini
 Steffen Allner
 Stephan Obermann
+Sven
 Sven-Hendrik Haase
 Sviatoslav Sydorenko
 Sylvain Marié

changelog/12749.feature.rst

@@ -0,0 +1,3 @@
+Add :confval:`collect_imported_tests`, when enabled (default is disabled) will make sure to not consider classes/functions which are imported by a test file and contains Test/test_*/*_test.
+
+-- by :user:`FreerGit`

src/_pytest/main.py

@@ -78,6 +78,12 @@
         type="args",
         default=[],
     )
+    parser.addini(
+        "collect_imported_tests",
+        "Whether to collect tests in imported modules outside `testpaths`",
+        type="bool",
+        default=False,
+    )
     group = parser.getgroup("general", "Running and selection options")
     group._addoption(
         "-x",
@@ -958,16 +964,41 @@
             self.trace.root.indent -= 1
 
     def genitems(self, node: nodes.Item | nodes.Collector) -> Iterator[nodes.Item]:
+        import inspect
+
+        from _pytest.python import Class
+        from _pytest.python import Function
+        from _pytest.python import Module
+
         self.trace("genitems", node)
         if isinstance(node, nodes.Item):
             node.ihook.pytest_itemcollected(item=node)
+            if self.config.getini("collect_imported_tests"):
+                if isinstance(node.parent, Module) and isinstance(node, Function):
+                    if inspect.isfunction(node._getobj()):
+                        fn_defined_at = node._getobj().__module__
+                        in_module = node.parent._getobj().__name__
+                        if fn_defined_at != in_module:
+                            return
             yield node
         else:
             assert isinstance(node, nodes.Collector)
             keepduplicates = self.config.getoption("keepduplicates")
             # For backward compat, dedup only applies to files.
             handle_dupes = not (keepduplicates and isinstance(node, nodes.File))
             rep, duplicate = self._collect_one_node(node, handle_dupes)
+
+            if self.config.getini("collect_imported_tests"):
+                for subnode in rep.result:
+                    if isinstance(subnode, Class) and isinstance(
+                        subnode.parent, Module
+                    ):
+                        if inspect.isclass(subnode._getobj()):
+                            class_defined_at = subnode._getobj().__module__
+                            in_module = subnode.parent._getobj().__name__
+                            if class_defined_at != in_module:
+                                rep.result.remove(subnode)
+
             if duplicate and not keepduplicates:
                 return
             if rep.passed:

testing/test_collect_imports.py

@@ -0,0 +1,150 @@
+from __future__ import annotations
+
+import textwrap
+
+from _pytest.pytester import Pytester
+
+
+def run_import_class_test(pytester: Pytester, passed: int = 0, errors: int = 0) -> None:
+    src_dir = pytester.mkdir("src")
+    tests_dir = pytester.mkdir("tests")
+    src_file = src_dir / "foo.py"
+
+    src_file.write_text(
+        textwrap.dedent("""\
+    class Testament(object):
+        def __init__(self):
+            super().__init__()
+            self.collections = ["stamp", "coin"]
+
+        def personal_property(self):
+            return [f"my {x} collection" for x in self.collections]
+    """),
+        encoding="utf-8",
+    )
+
+    test_file = tests_dir / "foo_test.py"
+    test_file.write_text(
+        textwrap.dedent("""\
+    import sys
+    import os
+
+    current_file = os.path.abspath(__file__)
+    current_dir = os.path.dirname(current_file)
+    parent_dir = os.path.abspath(os.path.join(current_dir, '..'))
+    sys.path.append(parent_dir)
+
+    from src.foo import Testament
+
+    class TestDomain:
+        def test_testament(self):
+            testament = Testament()
+            assert testament.personal_property()
+    """),
+        encoding="utf-8",
+    )
+
+    result = pytester.runpytest()
+    result.assert_outcomes(passed=passed, errors=errors)
+
+
+def test_collect_imports_disabled(pytester: Pytester) -> None:
+    pytester.makeini("""
+        [pytest]
+        testpaths = "tests"
+        collect_imported_tests = false
+    """)
+
+    run_import_class_test(pytester, errors=1)
+
+
+def test_collect_imports_default(pytester: Pytester) -> None:
+    pytester.makeini("""
+        [pytest]
+        testpaths = "tests"
+    """)
+
+    run_import_class_test(pytester, errors=1)
+
+
+def test_collect_imports_enabled(pytester: Pytester) -> None:
+    pytester.makeini("""
+        [pytest]
+        testpaths = "tests"
+        collect_imported_tests = true
+    """)
+
+    run_import_class_test(pytester, passed=1)
+
+
+def run_import_functions_test(
+    pytester: Pytester, passed: int, errors: int, failed: int
+) -> None:
+    src_dir = pytester.mkdir("src")
+    tests_dir = pytester.mkdir("tests")
+
+    src_file = src_dir / "foo.py"
+
+    # Note that these "tests" are should _not_ be treated as tests.
+    # They are normal functions that happens to have test_* or *_test in the name.
+    # Thus should _not_ be collected!
+    src_file.write_text(
+        textwrap.dedent("""\
+        def test_function():
+            some_random_computation = 5
+            return some_random_computation
+
+        def test_bar():
+            pass
+    """),
+        encoding="utf-8",
+    )
+
+    test_file = tests_dir / "foo_test.py"
+
+    # Inferred from the comment above, this means that there is _only_ one actual test
+    # which should result in only 1 passing test being ran.
+    test_file.write_text(
+        textwrap.dedent("""\
+    import sys
+    import os
+
+    current_file = os.path.abspath(__file__)
+    current_dir = os.path.dirname(current_file)
+    parent_dir = os.path.abspath(os.path.join(current_dir, '..'))
+    sys.path.append(parent_dir)
+
+    from src.foo import *
+
+    class TestDomain:
+        def test_important(self):
+            res = test_function()
+            if res == 5:
+                pass
+
+    """),
+        encoding="utf-8",
+    )
+
+    result = pytester.runpytest()
+    result.assert_outcomes(passed=passed, errors=errors, failed=failed)
+
+
+def test_collect_function_imports_enabled(pytester: Pytester) -> None:
+    pytester.makeini("""
+        [pytest]
+        testpaths = "tests"
+        collect_imported_tests = true
+    """)
+
+    run_import_functions_test(pytester, passed=1, errors=0, failed=0)
+
+
+def test_collect_function_imports_disabled(pytester: Pytester) -> None:
+    pytester.makeini("""
+        [pytest]
+        testpaths = "tests"
+        collect_imported_tests = false
+    """)
+
+    run_import_functions_test(pytester, passed=2, errors=0, failed=1)