Restore application configuration in spawned batch workers

tests/test_batch_configuration.py

@@ -0,0 +1,26 @@
+from pathlib import Path
+
+import pytest
+from great_ai import GreatAI, ParallelTinyDbDriver, RouteConfig, configure
+from great_ai.context import get_context
+
+
+def test_spawn_batch_uses_parent_configuration(
+    isolated_context: None, tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    database = tmp_path / "custom-traces.json"
+    monkeypatch.setattr(ParallelTinyDbDriver, "path_to_db", database)
+    configure(
+        prediction_cache_size=7,
+        disable_se4ml_banner=True,
+        route_config=RouteConfig(dashboard_enabled=False),
+    )
+
+    @GreatAI.create
+    def predict(value: int) -> int:
+        return get_context().prediction_cache_size + value
+
+    monkeypatch.setattr("multiprocessing.get_all_start_methods", lambda: ["spawn"])
+    assert [t.output for t in predict.process_batch([1, 2], concurrency=1)] == [8, 9]
+    assert database.exists()
+    assert len(get_context().tracing_database.query()[0]) == 2