Merge branch 'bschubert/stricter-thread-checks' into 'master'

_fixtures.py: Only get the normal number of threads at the start of session

See merge request BuildStream/buildstream!2038

3 files changed, 17 insertions, 6 deletions

diff --git a/src/buildstream/testing/_fixtures.py b/src/buildstream/testing/_fixtures.py
index 5da51bb45..98778936d 100644
--- a/src/buildstream/testing/_fixtures.py
+++ b/src/buildstream/testing/_fixtures.py
@@ -14,19 +14,26 @@
 #  You should have received a copy of the GNU Lesser General Public
 #  License along with this library. If not, see <http://www.gnu.org/licenses/>.
 
+# pylint: disable=redefined-outer-name
+
 import psutil
 import pytest
 
 from buildstream import node, utils
 
-# Catch tests that don't shut down background threads, which could then lead
-# to other tests hanging when BuildStream uses fork().
-@pytest.fixture(autouse=True)
-def thread_check():
+
+@pytest.fixture(autouse=True, scope="session")
+def default_thread_number():
     # xdist/execnet has its own helper thread.
     # Ignore that for `utils._is_single_threaded` checks.
     utils._INITIAL_NUM_THREADS_IN_MAIN_PROCESS = psutil.Process().num_threads()
 
+
+# Catch tests that don't shut down background threads, which could then lead
+# to other tests hanging when BuildStream uses fork().
+@pytest.fixture(autouse=True)
+def thread_check(default_thread_number):
+    assert utils._is_single_threaded()
     yield
     assert utils._is_single_threaded()
 
diff --git a/src/buildstream/testing/_sourcetests/conftest.py b/src/buildstream/testing/_sourcetests/conftest.py
index 64dd404ef..6790712a9 100644
--- a/src/buildstream/testing/_sourcetests/conftest.py
+++ b/src/buildstream/testing/_sourcetests/conftest.py
@@ -14,4 +14,4 @@
 #  You should have received a copy of the GNU Lesser General Public
 #  License along with this library. If not, see <http://www.gnu.org/licenses/>.
 
-from .._fixtures import reset_global_node_state, thread_check  # pylint: disable=unused-import
+from .._fixtures import reset_global_node_state, default_thread_number, thread_check  # pylint: disable=unused-import
diff --git a/tests/conftest.py b/tests/conftest.py
index 28e120d5e..476113105 100755
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -25,7 +25,11 @@ import pkg_resources
 import pytest
 
 from buildstream.testing import register_repo_kind, sourcetests_collection_hook
-from buildstream.testing._fixtures import reset_global_node_state, thread_check  # pylint: disable=unused-import
+from buildstream.testing._fixtures import (  # pylint: disable=unused-import
+    default_thread_number,
+    reset_global_node_state,
+    thread_check,
+)
 from buildstream.testing.integration import integration_cache  # pylint: disable=unused-import