feat(test_build_system): add buildv2_skip marker

This marker enables the skipping of tests that, for any reason, cannot
be executed with the IDF build system version 2. It accepts an optional
string argument that explains why the test cannot be run with version 2.
If no explanation is provided, a default message is used. This marker is
used in the `pytest_collection_modifyitems` hook to skip tests marked
with it when the `--buildv2` pytest command line option is used.

Signed-off-by: Frantisek Hrbata <frantisek.hrbata@espressif.com>

tools/test_build_system/conftest.py

@@ -10,7 +10,10 @@ from pathlib import Path
 from tempfile import mkdtemp
 
 import pytest
+from _pytest.config import Config
 from _pytest.fixtures import FixtureRequest
+from _pytest.main import Session
+from _pytest.nodes import Item
 from test_build_system_helpers import EXT_IDF_PATH
 from test_build_system_helpers import EnvDict
 from test_build_system_helpers import IdfPyFunc
@@ -235,3 +238,13 @@ def idf_py(default_idf_env: EnvDict) -> IdfPyFunc:
         return run_idf_py(*args, env=default_idf_env, workdir=os.getcwd(), check=check, input_str=input_str)  # type: ignore
 
     return result
+
+
+def pytest_collection_modifyitems(session: Session, config: Config, items: list[Item]) -> None:
+    if not config.getoption('--buildv2', False):
+        return
+    for item in items:
+        marker = item.get_closest_marker('buildv2_skip')
+        if marker:
+            reason = marker.args[0] if marker.args else 'Skipped as this test is specific to build system v1.'
+            item.add_marker(pytest.mark.skip(reason=reason))