chore: import upstream snapshot with attribution

tests/haystack/conftest.py

@@ -0,0 +1,23 @@
+import pytest
+from opentelemetry import trace as otel_trace
+
+import mlflow
+from mlflow.tracing.provider import provider
+from mlflow.utils.autologging_utils import AUTOLOGGING_INTEGRATIONS
+
+
+@pytest.fixture(autouse=True)
+def clear_autolog_state(reset_tracing):
+
+    for key in list(AUTOLOGGING_INTEGRATIONS.keys()):
+        AUTOLOGGING_INTEGRATIONS[key].clear()
+    mlflow.utils.import_hooks._post_import_hooks = {}
+
+    yield
+
+    # Reset OTel provider state for test isolation when switching between
+    # MLFLOW_USE_DEFAULT_TRACER_PROVIDER modes (pattern from test_integration.py)
+    otel_trace._TRACER_PROVIDER = None
+    otel_trace._TRACER_PROVIDER_SET_ONCE._done = False
+    provider._global_provider_init_once._done = False
+    provider._isolated_tracer_provider_once._done = False