Add support for distributed run

When tests are distributed, a copy of the database is created for each worker at the start of the test session. This is useful to avoid concurrent access to the same database, which can lead to deadlocks. The provided database is therefore used only as template. At the end of the tests, all the created databases are dropped.

README.rst

@@ -51,6 +51,8 @@ You can use the ``ODOO_RC`` environment variable using an odoo configuration fil
    export ODOO_RC=/path/to/odoo/config.cfg
    pytest ...
 
+The plugin is also compatible with distributed run provided by the `pytest-xdist <https://pypi.org/project/pytest-xdist/>`_ library. When tests are distributed, a copy of the database is created for each worker at the start of the test session.
+This is useful to avoid concurrent access to the same database, which can lead to deadlocks. The provided database is therefore used only as template. At the end of the tests, all the created databases are dropped.
 
 Known issues
 ------------

pytest_odoo.py

@@ -9,6 +9,7 @@
 import signal
 import sys
 import threading
+from contextlib import contextmanager
 from pathlib import Path
 from typing import Optional
 
@@ -112,6 +113,30 @@ def load_http(request):
         signal.signal(signal.SIGINT, signal.default_int_handler)
 
 
+@contextmanager
+def _worker_db_name():
+    # This method ensure that if tests are ran in a distributed way
+    # thanks to the use of pytest-xdist addon, each worker will use
+    # a specific copy of the initial database to run their tests.
+    # In this way we prevent deadlock errors.
+    xdist_worker = os.getenv("PYTEST_XDIST_WORKER")
+    original_db_name = db_name = odoo.tests.common.get_db_name()
+    try:
+        if xdist_worker:
+            db_name = f"{original_db_name}-{xdist_worker}"
+            ret = os.system(f"psql -lqt | cut -d \| -f 1 | grep -w {db_name}")
+            if ret == 0:
+                os.system(f"dropdb {db_name}")
+            os.system(f"createdb -T {original_db_name} {db_name}")
+            odoo.tools.config["db_name"] = db_name
+        yield db_name
+    finally:
+        if db_name != original_db_name:
+            odoo.sql_db.close_db(db_name)
+            os.system(f"dropdb {db_name}")
+            odoo.tools.config["db_name"] = original_db_name
+
+
 @pytest.fixture(scope='session', autouse=True)
 def load_registry():
     # Initialize the registry before running tests.
@@ -123,7 +148,9 @@ def load_registry():
     # Finally we enable `testing` flag on current thread
     # since Odoo sets it when loading test suites.
     threading.current_thread().testing = True
-    odoo.registry(odoo.tests.common.get_db_name())
+    with _worker_db_name() as db_name:
+        odoo.registry(db_name)
+        yield
 
 
 @pytest.fixture(scope='module', autouse=True)