Intermediate changes

commit_hash:e6d634bd59f23a5fa99d8c54932926f775dab895

24 files changed, 568 insertions, 119 deletions

diff --git a/library/python/pytest/main.py b/library/python/pytest/main.py
index 6290ad5f659..c6be6ca802e 100644
--- a/library/python/pytest/main.py
+++ b/library/python/pytest/main.py
@@ -56,7 +56,7 @@ def main():
 
     test_modules = [
         # fmt: off
-        name[len(prefix) :]
+        name
         for name in sys.extra_modules
         if name.startswith(prefix) and not name.endswith('.conftest')
         # fmt: on
diff --git a/library/python/pytest/module_utils.py b/library/python/pytest/module_utils.py
new file mode 100644
index 00000000000..a26deccfecb
--- /dev/null
+++ b/library/python/pytest/module_utils.py
@@ -0,0 +1,83 @@
+import os
+
+import yatest.common
+import __res
+
+
+def is_relative_to(path, parent):
+    """
+    A polyfill for pathlib.Path.is_relative_to (string-based implementation).
+    Does NOT involve filesystem operations.
+    """
+    path = os.path.normpath(path)
+    parent = os.path.normpath(parent)
+
+    if path == parent:
+        return True
+
+    if not parent.endswith(os.sep):
+        parent += os.sep
+
+    return path.startswith(parent)
+
+
+def relative_to(path, parent):
+    """
+    A polyfill for pathlib.Path.relative_to (string-based implementation).
+    Does NOT involve filesystem operations.
+    """
+    path = os.path.normpath(path)
+    parent = os.path.normpath(parent)
+
+    if path == parent:
+        return ''
+
+    if not parent.endswith(os.sep):
+        parent += os.sep
+
+    # Check if path starts with parent
+    if not path.startswith(parent):
+        raise ValueError('Path {} is not relative to {}', path, parent)
+
+    return path[len(parent) :]
+
+
+def get_module_file_path(module_name):
+    """
+    Get the file path for a module without importing it.
+    For synthesized empty __init__.py modules, returns module_name as a fake file path.
+    """
+    return __res.importer.get_filename(module_name)
+
+
+_BASE_PATHS = None
+
+
+def get_proper_module_path(module_name):
+    """
+    Get the file path for a test module relative to the repository root.
+    For synthesized empty __init__.py modules, returns module_name as a fake file path.
+    """
+    global _BASE_PATHS
+    if _BASE_PATHS is None:
+        _BASE_PATHS = (
+            str(yatest.common.source_path()),
+            str(yatest.common.work_path()),
+            str(yatest.common.build_path()),
+        )
+
+    path = get_module_file_path(module_name)
+
+    if not os.path.isabs(path):
+        if path == module_name:
+            # Synthesized __init__.py module.
+            return None
+        return path
+
+    for base_path in _BASE_PATHS:
+        if is_relative_to(path, base_path):
+            return relative_to(path, base_path)
+
+    raise ValueError(
+        'Failed to resolve module "{}" with path="{}" against known base paths'.format(module_name, path),
+    )
diff --git a/library/python/pytest/plugins/collection.py b/library/python/pytest/plugins/collection.py
index e9940d8dacb..814649ac17f 100644
--- a/library/python/pytest/plugins/collection.py
+++ b/library/python/pytest/plugins/collection.py
@@ -1,67 +1,78 @@
+import json
 import os
 import sys
-from six import reraise
 import logging
 
 import py
-
-import pytest  # noqa
-import _pytest.python
+import pytest
 import _pytest.doctest
-import json
-import library.python.testing.filter.filter as test_filter
+import six
+from six import reraise
 
-if sys.version_info > (3,):
-    import _pytest.stash
+if six.PY3:
+    import pathlib
 
+from library.python.pytest import module_utils
+import library.python.testing.filter.filter as test_filter
 
-class LoadedModule(_pytest.python.Module):
-    def __init__(self, parent, name, **kwargs):
-        self.name = name + '.py'
-        self.session = parent
-        self.parent = parent
-        self.config = parent.config
-        self.keywords = {}
-        self.own_markers = []
-        self.extra_keyword_matches = set()
-        self.fspath = py.path.local()
-        if sys.version_info > (3,):
-            self.stash = _pytest.stash.Stash()
 
-    @classmethod
-    def from_parent(cls, **kwargs):
-        namespace = kwargs.pop('namespace', True)
-        kwargs.setdefault('fspath', py.path.local())
+class LoadedModule(pytest.Module):
+    def __init__(self, parent, name, namespace=True, **kwargs):
+        self.module_name = name
+        if namespace:
+            assert name.startswith('__tests__.')
+            self.display_module_name = name[len('__tests__.'):]
+        else:
+            self.display_module_name = name
+        self.is_fake_module = False
+        # Always passed to `super().__init__` explicitly.
+        kwargs.pop('nodeid', None)
 
-        loaded_module = getattr(super(LoadedModule, cls), 'from_parent', cls)(**kwargs)
-        loaded_module.namespace = namespace
+        if os.getenv('CONFTEST_LOAD_POLICY') == 'LOCAL':
+            nodeid = module_utils.get_proper_module_path(self.module_name)
+            if nodeid is None:
+                self.is_fake_module = True
+                return
 
-        return loaded_module
+            name = nodeid
+            if six.PY3:
+                kwargs['path'] = kwargs.get('path') or pathlib.Path(nodeid)
+            else:
+                raw_module_path = module_utils.get_module_file_path(self.module_name)
+                kwargs['fspath'] = kwargs.get('fspath') or py.path.local(raw_module_path)
+        else:
+            nodeid = self.display_module_name + '.py'
+            name = nodeid
+            if six.PY3:
+                kwargs['path'] = kwargs.get('path') or pathlib.Path(py.path.local())
+            else:
+                kwargs['fspath'] = kwargs.get('fspath') or py.path.local()
 
-    @property
-    def _nodeid(self):
-        if os.getenv('CONFTEST_LOAD_POLICY') == 'LOCAL':
-            return self._getobj().__file__
+        if six.PY3:
+            super().__init__(parent=parent, name=name, nodeid=nodeid, **kwargs)
         else:
-            return self.name
+            super(LoadedModule, self).__init__(parent=parent, nodeid=nodeid, **kwargs)
+            self.name = name
 
-    @property
-    def nodeid(self):
-        return self._nodeid
+    @classmethod
+    def from_parent(cls, **kwargs):
+        return getattr(super(LoadedModule, cls), 'from_parent', cls)(**kwargs)
 
     def _getobj(self):
-        module_name = self.name[:-len('.py')]
-        if self.namespace:
-            module_name = '__tests__.' + module_name
+        # A simplified version of pytest `importtestmodule` that works with resfs.
         try:
-            __import__(module_name)
+            __import__(self.module_name)
+        except pytest.skip.Exception as e:
+            if not e.allow_module_level:
+                raise RuntimeError("Using pytest.skip outside of a test will skip the entire module. If that's your intention, pass `allow_module_level=True`.")
+            raise
         except Exception as e:
-            msg = 'Failed to load module "{}" and obtain list of tests due to an error'.format(module_name)
+            msg = 'Failed to load module "{}" and obtain list of tests due to an error'.format(self.module_name)
             logging.exception('%s: %s', msg, e)
             etype, exc, tb = sys.exc_info()
             reraise(etype, type(exc)('{}\n{}'.format(exc, msg)), tb)
 
-        return sys.modules[module_name]
+        return sys.modules[self.module_name]
 
 
 class DoctestModule(LoadedModule):
@@ -72,14 +83,14 @@ class DoctestModule(LoadedModule):
         module = self._getobj()
         # uses internal doctest module parsing mechanism
         finder = doctest.DocTestFinder()
-        if sys.version_info > (3,):
+        if six.PY3:
             optionflags = _pytest.doctest.get_optionflags(self.config)
         else:
             optionflags = _pytest.doctest.get_optionflags(self)
         runner = doctest.DebugRunner(verbose=0, optionflags=optionflags)
 
         try:
-            for test in finder.find(module, self.name[:-len('.py')]):
+            for test in finder.find(module, self.display_module_name):
                 if test.examples:  # skip empty doctests
                     yield getattr(_pytest.doctest.DoctestItem, 'from_parent', _pytest.doctest.DoctestItem)(
                         name=test.name,
@@ -93,34 +104,45 @@ class DoctestModule(LoadedModule):
             reraise(etype, type(exc)('{}\n{}'.format(exc, msg)), tb)
 
 
-def _is_skipped_module_level(module):
-    # since we import module by ourselves when CONFTEST_LOAD_POLICY is set to LOCAL we have to handle
-    # pytest.skip.Exception https://docs.pytest.org/en/stable/reference/reference.html#pytest-skip
-    try:
-        module.obj
-    except pytest.skip.Exception as e:
-        if not e.allow_module_level:
-            raise RuntimeError("Using pytest.skip outside of a test will skip the entire module. If that's your intention, pass `allow_module_level=True`.")
+# NOTE: Since we are overriding collect method of pytest session, pytest hooks are not invoked during collection.
+# This function is only used in CollectionPlugin below, this is not an implementation of a pytest hook.
+def _pytest_ignore_collect(module, config, filenames_from_full_filters, accept_filename_predicate):
+    if module.is_fake_module:
         return True
-    except Exception:
-        # letting other exceptions such as ImportError slip through
-        pass
-    return False
 
+    # TODO refactor to use meaningful attributes like `path` instead?
+    #  test_file_filter would need to be relative to repository root.
+    legacy_name = module.display_module_name + '.py'
 
-# NOTE: Since we are overriding collect method of pytest session, pytest hooks are not invoked during collection.
-def pytest_ignore_collect(module, session, filenames_from_full_filters, accept_filename_predicate):
-    if session.config.option.mode == 'list':
-        return not accept_filename_predicate(module.name) or _is_skipped_module_level(module)
+    if config.option.mode == 'list':
+        return not accept_filename_predicate(legacy_name)
 
-    if filenames_from_full_filters is not None and module.name not in filenames_from_full_filters:
+    if filenames_from_full_filters is not None and legacy_name not in filenames_from_full_filters:
         return True
 
-    test_file_filter = getattr(session.config.option, 'test_file_filter', None)
-    if test_file_filter and module.name != test_file_filter.replace('/', '.'):
+    test_file_filter = getattr(config.option, 'test_file_filter', None)
+    if test_file_filter and legacy_name != test_file_filter.replace('/', '.'):
         return True
 
-    return _is_skipped_module_level(module)
+    return False
+
+
+def _patch_set_initial_conftests(pluginmanager):
+    """
+    Avoids attempts to access filesystem directly in built-in `pytest_load_initial_conftests` hook impl.
+    """
+    if six.PY3:
+        def _set_initial_conftests_py3(pyargs, noconftest, *args, **kwargs):
+            pluginmanager._noconftest = noconftest
+            pluginmanager._using_pyargs = pyargs
+
+        pluginmanager._set_initial_conftests = _set_initial_conftests_py3
+    else:
+        def _set_initial_conftests_py2(namespace):
+            pluginmanager._noconftest = namespace.noconftest
+            pluginmanager._using_pyargs = namespace.pyargs
+
+        pluginmanager._set_initial_conftests = _set_initial_conftests_py2
 
 
 class CollectionPlugin(object):
@@ -128,27 +150,37 @@ class CollectionPlugin(object):
         self._test_modules = test_modules
         self._doctest_modules = doctest_modules
 
+    @pytest.hookimpl(tryfirst=True)
+    def pytest_load_initial_conftests(self, early_config):
+        _patch_set_initial_conftests(early_config.pluginmanager)
+
     def pytest_sessionstart(self, session):
 
         def collect(*args, **kwargs):
-            accept_filename_predicate = test_filter.make_py_file_filter(session.config.option.test_filter)
-            full_test_names_file_path = session.config.option.test_list_path
+            config = session.config
+
+            if os.getenv('CONFTEST_LOAD_POLICY') == 'LOCAL':
+                # A custom function that is set in conftests.py.
+                config._ya_register_non_initial_conftests()
+
+            accept_filename_predicate = test_filter.make_py_file_filter(config.option.test_filter)
+            full_test_names_file_path = config.option.test_list_path
             filenames_filter = None
 
             if full_test_names_file_path and os.path.exists(full_test_names_file_path):
                 with open(full_test_names_file_path, 'r') as afile:
                     # in afile stored 2 dimensional array such that array[modulo_index] contains tests which should be run in this test suite
-                    full_names_filter = set(json.load(afile)[int(session.config.option.modulo_index)])
+                    full_names_filter = set(json.load(afile)[int(config.option.modulo_index)])
                     filenames_filter = set(map(lambda x: x.split('::')[0], full_names_filter))
 
             for test_module in self._test_modules:
                 module = LoadedModule.from_parent(name=test_module, parent=session)
-                if not pytest_ignore_collect(module, session, filenames_filter, accept_filename_predicate):
+                if not _pytest_ignore_collect(module, config, filenames_filter, accept_filename_predicate):
                     yield module
 
                 if os.environ.get('YA_PYTEST_DISABLE_DOCTEST', 'no') == 'no':
                     module = DoctestModule.from_parent(name=test_module, parent=session)
-                    if not pytest_ignore_collect(module, session, filenames_filter, accept_filename_predicate):
+                    if not _pytest_ignore_collect(module, config, filenames_filter, accept_filename_predicate):
                         yield module
 
             if os.environ.get('YA_PYTEST_DISABLE_DOCTEST', 'no') == 'no':
diff --git a/library/python/pytest/plugins/conftests.py b/library/python/pytest/plugins/conftests.py
index 4af60b1a049..7d8c13d93ee 100644
--- a/library/python/pytest/plugins/conftests.py
+++ b/library/python/pytest/plugins/conftests.py
@@ -1,62 +1,144 @@
-import os
+import collections
+import functools
 import importlib
-import sys
 import inspect
+import os
+import six
+import sys
 
-import yatest.common as yc
-
-from pytest import hookimpl
-from yatest_lib.ya import Ya
+import pytest
 
 from library.python.pytest.plugins.fixtures import metrics, links  # noqa
+from library.python.pytest import module_utils
+import yatest.common
+import yatest_lib.ya
 
-orig_getfile = inspect.getfile
+ConftestInfo = collections.namedtuple('ConftestInfo', ['module_name', 'proper_path'])
+LoadedConftestInfo = collections.namedtuple('LoadedConftestInfo', ['conftest_dir', 'module'])
+
+
+def _patch_inspect_getfile():
+    orig_getfile = inspect.getfile
+
+    def getfile(object):
+        if inspect.ismodule(object) and getattr(object, '__orig_file__', None):
+            res = object.__orig_file__
+        else:
+            res = orig_getfile(object)
+        return res
 
+    inspect.getfile = getfile
 
-def getfile(object):
-    if inspect.ismodule(object) and getattr(object, '__orig_file__', None):
-        res = object.__orig_file__
+
+def _consider_conftest(pluginmanager, module, registration_name):
+    if six.PY3:
+        pluginmanager.consider_conftest(module, registration_name=registration_name)
     else:
-        res = orig_getfile(object)
-    return res
+        pluginmanager.consider_conftest(module)
 
 
-inspect.getfile = getfile
-conftest_modules = []
+def _import_conftest(pluginmanager, module_name, proper_path):
+    """Essentially PytestPluginManager._importconftest, adapted to resource-based conftest modules."""
+    module = importlib.import_module(module_name)
 
+    if six.PY3:
+        pluginmanager._check_non_top_pytest_plugins(module, proper_path)
 
-@hookimpl(trylast=True)
-def pytest_load_initial_conftests(early_config, parser, args):
-    yc.runtime._set_ya_config(ya=Ya())
+    _consider_conftest(pluginmanager, module, proper_path)
+    conftest_info = LoadedConftestInfo(conftest_dir=os.path.dirname(proper_path), module=module)
+    pluginmanager._ya_loaded_conftest_infos.append(conftest_info)
 
-    if hasattr(sys, 'extra_modules'):
-        conftests = filter(lambda name: name.endswith(".conftest"), sys.extra_modules)
-    else:
-        conftests = []
 
-    def conftest_key(name):
-        if not name.startswith("__tests__."):
-            # Make __tests__ come last
-            return "_." + name
-        return name
+def _getconftestmodules_local(self, path):
+    """
+    _getconftestmodules returns a cached list of conftest modules that relate to the given test path.
+    This list is then used by pytest to temporarily mute other non-initial conftests when processing those tests.
+    We patch pytest's implementation to avoid fs access when discovering conftests and in is_file() checks.
+    """
+    path = str(path)
+    if path.endswith('.py'):
+        path = os.path.dirname(path)
 
-    for name in sorted(conftests, key=conftest_key):
-        mod = importlib.import_module(name)
-        if os.getenv("CONFTEST_LOAD_POLICY") != "LOCAL":
-            mod.__orig_file__ = mod.__file__
-            mod.__file__ = ""
-        conftest_modules.append(mod)
-        if sys.version_info > (3,):
-            early_config.pluginmanager.consider_conftest(mod, registration_name=mod.__file__)
-        else:
-            early_config.pluginmanager.consider_conftest(mod)
+    cache = self._ya_getconftestmodules_cache
+    if path not in cache:
+        cache[path] = [
+            conftest_info.module
+            for conftest_info in self._ya_loaded_conftest_infos
+            if module_utils.is_relative_to(path, conftest_info.conftest_dir)
+        ]
+
+    return cache[path]
+
+
+def _getconftestmodules_non_local(path):
+    return _conftest_modules
+
+
+_conftest_modules = []
+
+
[email protected](trylast=True)
+def pytest_load_initial_conftests(early_config):
+    pluginmanager = early_config.pluginmanager
+
+    yatest.common.runtime._set_ya_config(ya=yatest_lib.ya.Ya())
+
+    conftests = filter(lambda name: name.endswith('.conftest'), getattr(sys, 'extra_modules', []))
+
+    if os.getenv('CONFTEST_LOAD_POLICY') == 'LOCAL':
+        test_dir = str(yatest.common.context.project_path)
+
+        initial_conftests = []
+        non_initial_conftests = []
+
+        for module_name in conftests:
+            proper_path = module_utils.get_proper_module_path(module_name)
+            assert proper_path is not None
+            conftest_dir = os.path.dirname(proper_path)
+
+            # There are two kinds of relevant conftests:
+            # - Initial: conftest is in the directory of the test suite or in a parent directory (applies to all tests)
+            # - Non-initial: conftest is strictly within the test directory
+            if module_utils.is_relative_to(test_dir, conftest_dir):
+                initial_conftests.append(ConftestInfo(module_name=module_name, proper_path=proper_path))
+            elif module_utils.is_relative_to(conftest_dir, test_dir):
+                non_initial_conftests.append(ConftestInfo(module_name=module_name, proper_path=proper_path))
+
+        # Ensure parent conftests are loaded before child conftests
+        initial_conftests.sort(key=lambda x: len(x.proper_path))
+        non_initial_conftests.sort(key=lambda x: len(x.proper_path))
+
+        pluginmanager._ya_loaded_conftest_infos = []
+        pluginmanager._ya_getconftestmodules_cache = {}
+
+        for conftest_info in initial_conftests:
+            _import_conftest(pluginmanager, conftest_info.module_name, conftest_info.proper_path)
+
+        pluginmanager._getconftestmodules = functools.partial(_getconftestmodules_local, pluginmanager)
+
+        def _ya_register_non_initial_conftests():
+            for conftest_info in non_initial_conftests:
+                _import_conftest(pluginmanager, conftest_info.module_name, conftest_info.proper_path)
+
+        # See collection.py, non-initial conftests are registered at the start of collection phase, like in vanilla.
+        # Alas, stash is not available in py2.
+        early_config._ya_register_non_initial_conftests = _ya_register_non_initial_conftests
+    else:
+        _patch_inspect_getfile()
+
+        def conftest_key(name):
+            if not name.startswith('__tests__.'):
+                # Make __tests__ come last
+                return '_.' + name
+            return name
 
+        for name in sorted(conftests, key=conftest_key):
+            module = importlib.import_module(name)
 
-def getconftestmodules(*args, **kwargs):
-    return conftest_modules
+            setattr(module, '__orig_file__', module.__file__)
+            module.__file__ = ''
 
+            _conftest_modules.append(module)
+            _consider_conftest(pluginmanager, module, module.__file__)
 
-def pytest_sessionstart(session):
-    # Override filesystem based relevant conftest discovery on the call path
-    assert session.config.pluginmanager
-    session.config.pluginmanager._getconftestmodules = getconftestmodules
+        pluginmanager._getconftestmodules = _getconftestmodules_non_local
diff --git a/library/python/pytest/ut/conftest_local/initial_conftests/conftest.py b/library/python/pytest/ut/conftest_local/initial_conftests/conftest.py
new file mode 100644
index 00000000000..c63568e2aca
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/initial_conftests/conftest.py
@@ -0,0 +1,21 @@
+"""
+This conftest SHOULD be counted an initial conftest, see
+https://docs.pytest.org/en/stable/how-to/writing_plugins.html#pluginorder
+
+This is because this conftest is located in a parent directory of the test module.
+"""
+
+import pytest
+
+
+sessionstart_called = False
+
+
+def pytest_sessionstart(session):
+    global sessionstart_called
+    sessionstart_called = True
+
+
[email protected]
+def is_sessionstart_called_root():
+    return sessionstart_called
diff --git a/library/python/pytest/ut/conftest_local/initial_conftests/foo/bar/conftest.py b/library/python/pytest/ut/conftest_local/initial_conftests/foo/bar/conftest.py
new file mode 100644
index 00000000000..3fb6b3f64d6
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/initial_conftests/foo/bar/conftest.py
@@ -0,0 +1,21 @@
+"""
+This conftest should NOT be counted an initial conftest, see
+https://docs.pytest.org/en/stable/how-to/writing_plugins.html#pluginorder
+
+This is because this conftest is located in a subdirectory of the test module.
+"""
+
+import pytest
+
+
+sessionstart_called = False
+
+
+def pytest_sessionstart(session):
+    global sessionstart_called
+    sessionstart_called = True
+
+
[email protected]
+def is_sessionstart_called_bar():
+    return sessionstart_called
diff --git a/library/python/pytest/ut/conftest_local/initial_conftests/foo/bar/test_initial_conftests.py b/library/python/pytest/ut/conftest_local/initial_conftests/foo/bar/test_initial_conftests.py
new file mode 100644
index 00000000000..88fcaf28062
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/initial_conftests/foo/bar/test_initial_conftests.py
@@ -0,0 +1,4 @@
+def test_initial_conftests(is_sessionstart_called_root, is_sessionstart_called_foo, is_sessionstart_called_bar):
+    assert is_sessionstart_called_root
+    assert is_sessionstart_called_foo
+    assert not is_sessionstart_called_bar
diff --git a/library/python/pytest/ut/conftest_local/initial_conftests/foo/conftest.py b/library/python/pytest/ut/conftest_local/initial_conftests/foo/conftest.py
new file mode 100644
index 00000000000..fd826e553a6
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/initial_conftests/foo/conftest.py
@@ -0,0 +1,21 @@
+"""
+This conftest SHOULD be counted an initial conftest, see
+https://docs.pytest.org/en/stable/how-to/writing_plugins.html#pluginorder
+
+This is because this conftest is located in the directory of the test module.
+"""
+
+import pytest
+
+
+sessionstart_called = False
+
+
+def pytest_sessionstart(session):
+    global sessionstart_called
+    sessionstart_called = True
+
+
[email protected]
+def is_sessionstart_called_foo():
+    return sessionstart_called
diff --git a/library/python/pytest/ut/conftest_local/initial_conftests/foo/ya.make b/library/python/pytest/ut/conftest_local/initial_conftests/foo/ya.make
new file mode 100644
index 00000000000..d63c7f19f49
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/initial_conftests/foo/ya.make
@@ -0,0 +1,16 @@
+PY23_TEST()
+
+TEST_SRCS(
+    bar/test_initial_conftests.py
+)
+
+PEERDIR(
+    library/python/pytest
+    library/python/pytest/ut/conftest_local/initial_conftests
+)
+
+CONFTEST_LOAD_POLICY_LOCAL()
+
+STYLE_PYTHON()
+
+END()
diff --git a/library/python/pytest/ut/conftest_local/initial_conftests/ya.make b/library/python/pytest/ut/conftest_local/initial_conftests/ya.make
new file mode 100644
index 00000000000..083c7dcc33c
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/initial_conftests/ya.make
@@ -0,0 +1,15 @@
+PY23_LIBRARY()
+
+TEST_SRCS(
+    conftest.py
+    foo/conftest.py
+    foo/bar/conftest.py
+)
+
+STYLE_PYTHON()
+
+END()
+
+RECURSE_FOR_TESTS(
+    foo
+)
diff --git a/library/python/pytest/ut/conftest_local/single_test_module/foo/conftest.py b/library/python/pytest/ut/conftest_local/single_test_module/foo/conftest.py
new file mode 100644
index 00000000000..2f685ec112e
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/single_test_module/foo/conftest.py
@@ -0,0 +1,9 @@
+"""Conftest for foo directory - should NOT be loaded by foo_bar tests."""
+
+import pytest
+
+
[email protected]
+def foo_fixture():
+    """Fixture from foo/conftest.py that should NOT be available in foo_bar."""
+    return 'foo_fixture_value'
diff --git a/library/python/pytest/ut/conftest_local/single_test_module/foo_bar/conftest.py b/library/python/pytest/ut/conftest_local/single_test_module/foo_bar/conftest.py
new file mode 100644
index 00000000000..1e1bba2425d
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/single_test_module/foo_bar/conftest.py
@@ -0,0 +1,9 @@
+"""Conftest for foo_bar directory - should be loaded by foo_bar tests."""
+
+import pytest
+
+
[email protected]
+def foo_bar_fixture():
+    """Fixture from foo_bar/conftest.py that should be available in foo_bar tests."""
+    return 'foo_bar_fixture_value'
diff --git a/library/python/pytest/ut/conftest_local/single_test_module/foo_bar/test_something.py b/library/python/pytest/ut/conftest_local/single_test_module/foo_bar/test_something.py
new file mode 100644
index 00000000000..01de1d36a60
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/single_test_module/foo_bar/test_something.py
@@ -0,0 +1,23 @@
+"""Test file to reproduce pytest conftest bug.
+
+This test should only load foo_bar/conftest.py, but pytest incorrectly
+also loads foo/conftest.py because 'foo_bar' starts with 'foo'.
+"""
+
+import pytest
+
+
+def test_fixture_availability(request):
+    """Test which fixtures are available - should only have foo_bar_fixture."""
+    # This should work - foo_bar/conftest.py should be loaded
+    foo_bar_value = request.getfixturevalue('foo_bar_fixture')
+    assert foo_bar_value == 'foo_bar_fixture_value'
+
+    # This should fail - foo/conftest.py should NOT be loaded
+    with pytest.raises(LookupError):
+        request.getfixturevalue('foo_fixture')
+
+
+def test_simple():
+    """Simple test to verify basic functionality."""
+    assert True
diff --git a/library/python/pytest/ut/conftest_local/single_test_module/ya.make b/library/python/pytest/ut/conftest_local/single_test_module/ya.make
new file mode 100644
index 00000000000..e7ec5637e2a
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/single_test_module/ya.make
@@ -0,0 +1,13 @@
+PY23_TEST()
+
+ALL_PYTEST_SRCS(RECURSIVE)
+
+PEERDIR(
+    library/python/pytest
+)
+
+CONFTEST_LOAD_POLICY_LOCAL()
+
+STYLE_PYTHON()
+
+END()
diff --git a/library/python/pytest/ut/conftest_local/split_test_modules/foo/conftest.py b/library/python/pytest/ut/conftest_local/split_test_modules/foo/conftest.py
new file mode 100644
index 00000000000..2f685ec112e
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/split_test_modules/foo/conftest.py
@@ -0,0 +1,9 @@
+"""Conftest for foo directory - should NOT be loaded by foo_bar tests."""
+
+import pytest
+
+
[email protected]
+def foo_fixture():
+    """Fixture from foo/conftest.py that should NOT be available in foo_bar."""
+    return 'foo_fixture_value'
diff --git a/library/python/pytest/ut/conftest_local/split_test_modules/foo/ya.make b/library/python/pytest/ut/conftest_local/split_test_modules/foo/ya.make
new file mode 100644
index 00000000000..e8373b8be86
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/split_test_modules/foo/ya.make
@@ -0,0 +1,16 @@
+PY23_TEST()
+
+SIZE(SMALL)
+
+ALL_PYTEST_SRCS(ONLY_TEST_FILES)
+
+PEERDIR(
+    library/python/pytest
+    library/python/pytest/ut/conftest_local/split_test_modules
+)
+
+CONFTEST_LOAD_POLICY_LOCAL()
+
+STYLE_PYTHON()
+
+END()
diff --git a/library/python/pytest/ut/conftest_local/split_test_modules/foo_bar/conftest.py b/library/python/pytest/ut/conftest_local/split_test_modules/foo_bar/conftest.py
new file mode 100644
index 00000000000..1e1bba2425d
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/split_test_modules/foo_bar/conftest.py
@@ -0,0 +1,9 @@
+"""Conftest for foo_bar directory - should be loaded by foo_bar tests."""
+
+import pytest
+
+
[email protected]
+def foo_bar_fixture():
+    """Fixture from foo_bar/conftest.py that should be available in foo_bar tests."""
+    return 'foo_bar_fixture_value'
diff --git a/library/python/pytest/ut/conftest_local/split_test_modules/foo_bar/test_something.py b/library/python/pytest/ut/conftest_local/split_test_modules/foo_bar/test_something.py
new file mode 100644
index 00000000000..01de1d36a60
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/split_test_modules/foo_bar/test_something.py
@@ -0,0 +1,23 @@
+"""Test file to reproduce pytest conftest bug.
+
+This test should only load foo_bar/conftest.py, but pytest incorrectly
+also loads foo/conftest.py because 'foo_bar' starts with 'foo'.
+"""
+
+import pytest
+
+
+def test_fixture_availability(request):
+    """Test which fixtures are available - should only have foo_bar_fixture."""
+    # This should work - foo_bar/conftest.py should be loaded
+    foo_bar_value = request.getfixturevalue('foo_bar_fixture')
+    assert foo_bar_value == 'foo_bar_fixture_value'
+
+    # This should fail - foo/conftest.py should NOT be loaded
+    with pytest.raises(LookupError):
+        request.getfixturevalue('foo_fixture')
+
+
+def test_simple():
+    """Simple test to verify basic functionality."""
+    assert True
diff --git a/library/python/pytest/ut/conftest_local/split_test_modules/foo_bar/ya.make b/library/python/pytest/ut/conftest_local/split_test_modules/foo_bar/ya.make
new file mode 100644
index 00000000000..e8373b8be86
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/split_test_modules/foo_bar/ya.make
@@ -0,0 +1,16 @@
+PY23_TEST()
+
+SIZE(SMALL)
+
+ALL_PYTEST_SRCS(ONLY_TEST_FILES)
+
+PEERDIR(
+    library/python/pytest
+    library/python/pytest/ut/conftest_local/split_test_modules
+)
+
+CONFTEST_LOAD_POLICY_LOCAL()
+
+STYLE_PYTHON()
+
+END()
diff --git a/library/python/pytest/ut/conftest_local/split_test_modules/ya.make b/library/python/pytest/ut/conftest_local/split_test_modules/ya.make
new file mode 100644
index 00000000000..9067439b690
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/split_test_modules/ya.make
@@ -0,0 +1,15 @@
+PY23_LIBRARY()
+
+TEST_SRCS(
+    foo/conftest.py
+    foo_bar/conftest.py
+)
+
+STYLE_PYTHON()
+
+END()
+
+RECURSE_FOR_TESTS(
+    foo
+    foo_bar
+)
diff --git a/library/python/pytest/ut/conftest_local/ya.make b/library/python/pytest/ut/conftest_local/ya.make
new file mode 100644
index 00000000000..ba918e4d9cb
--- /dev/null
+++ b/library/python/pytest/ut/conftest_local/ya.make
@@ -0,0 +1,5 @@
+RECURSE_FOR_TESTS(
+    initial_conftests
+    single_test_module
+    split_test_modules
+)
diff --git a/library/python/pytest/ut/test_tools.py b/library/python/pytest/ut/test_tools.py
index 212a20fb174..3b23e550b22 100644
--- a/library/python/pytest/ut/test_tools.py
+++ b/library/python/pytest/ut/test_tools.py
@@ -48,10 +48,11 @@ def test_split_node_id_without_path(parameters, node_id, expected_class_name, ex
         ),
     ),
 )
-def test_split_node_id_with_path(mocker, parameters, node_id, expected_class_name, expected_test_name):
-    mocker.patch.object(sys, 'extra_modules', sys.extra_modules | {'__tests__.package.test_script'})
-    got = yatest_tools.split_node_id(node_id + parameters)
-    assert (expected_class_name, expected_test_name + parameters) == got
+def test_split_node_id_with_path(monkeypatch, parameters, node_id, expected_class_name, expected_test_name):
+    with monkeypatch.context() as context:
+        context.setattr(sys, 'extra_modules', sys.extra_modules | {'__tests__.package.test_script'})
+        got = yatest_tools.split_node_id(node_id + parameters)
+        assert (expected_class_name, expected_test_name + parameters) == got
 
 
 def test_missing_module(parameters):
@@ -84,7 +85,7 @@ def test_split_node_id_with_test_suffix(parameters, node_id, expected_class_name
     ],
 )
 def test_path_resolving_for_local_conftest_load_policy(
-    mocker, parameters, node_id, expected_class_name, expected_test_name
+    monkeypatch, parameters, node_id, expected_class_name, expected_test_name
 ):
     # Order matters
     extra_modules = [
@@ -92,9 +93,10 @@ def test_path_resolving_for_local_conftest_load_policy(
         '__tests__.test',
         '__tests__.a.test',
     ]
-    mocker.patch.object(sys, 'extra_modules', extra_modules)
-    got = yatest_tools.split_node_id(node_id + parameters)
-    assert (expected_class_name, expected_test_name + parameters) == got
+    with monkeypatch.context() as context:
+        context.setattr(sys, 'extra_modules', extra_modules)
+        got = yatest_tools.split_node_id(node_id + parameters)
+        assert (expected_class_name, expected_test_name + parameters) == got
 
 
 DATA = [
diff --git a/library/python/pytest/ut/ya.make b/library/python/pytest/ut/ya.make
index bb94c24c70b..8a93f4ae690 100644
--- a/library/python/pytest/ut/ya.make
+++ b/library/python/pytest/ut/ya.make
@@ -12,3 +12,7 @@ PEERDIR(
 STYLE_PYTHON()
 
 END()
+
+RECURSE_FOR_TESTS(
+    conftest_local
+)
diff --git a/library/python/pytest/ya.make b/library/python/pytest/ya.make
index 607aeb8218c..127d5851137 100644
--- a/library/python/pytest/ya.make
+++ b/library/python/pytest/ya.make
@@ -5,6 +5,7 @@ PY_SRCS(
     config.py
     context.py
     main.py
+    module_utils.py
     rewrite.py
     yatest_tools.py
 )