Updated test suite for explainability & provenance (#696)

* Provenance tests

* Embeddings tests

* Test librarian

* Test triples stream

* Test concurrency

* Entity centric graph writes

* Agent tool service tests

* Structured data tests

* RDF tests

* Addition LLM tests

* Reliability tests

tests/unit/test_reliability/test_metadata_preservation.py

@@ -0,0 +1,144 @@
+"""
+Tests for pipeline metadata preservation: DocumentMetadata and
+ProcessingMetadata round-trip through translators, field preservation,
+and default handling.
+"""
+
+import pytest
+
+from trustgraph.schema import DocumentMetadata, ProcessingMetadata, Triple, Term, IRI
+from trustgraph.messaging.translators.metadata import (
+    DocumentMetadataTranslator,
+    ProcessingMetadataTranslator,
+)
+
+
+# ---------------------------------------------------------------------------
+# DocumentMetadata translator
+# ---------------------------------------------------------------------------
+
+class TestDocumentMetadataTranslator:
+
+    def setup_method(self):
+        self.tx = DocumentMetadataTranslator()
+
+    def test_full_round_trip(self):
+        data = {
+            "id": "doc-123",
+            "time": 1710000000,
+            "kind": "application/pdf",
+            "title": "Test Document",
+            "comments": "No comments",
+            "metadata": [],
+            "user": "alice",
+            "tags": ["finance", "q4"],
+            "parent-id": "doc-100",
+            "document-type": "page",
+        }
+        obj = self.tx.to_pulsar(data)
+        assert obj.id == "doc-123"
+        assert obj.time == 1710000000
+        assert obj.kind == "application/pdf"
+        assert obj.title == "Test Document"
+        assert obj.user == "alice"
+        assert obj.tags == ["finance", "q4"]
+        assert obj.parent_id == "doc-100"
+        assert obj.document_type == "page"
+
+        wire = self.tx.from_pulsar(obj)
+        assert wire["id"] == "doc-123"
+        assert wire["user"] == "alice"
+        assert wire["parent-id"] == "doc-100"
+        assert wire["document-type"] == "page"
+
+    def test_defaults_for_missing_fields(self):
+        obj = self.tx.to_pulsar({})
+        assert obj.parent_id == ""
+        assert obj.document_type == "source"
+
+    def test_metadata_triples_preserved(self):
+        triple_wire = [{
+            "s": {"t": "i", "i": "http://example.org/s"},
+            "p": {"t": "i", "i": "http://example.org/p"},
+            "o": {"t": "i", "i": "http://example.org/o"},
+        }]
+        data = {"metadata": triple_wire}
+        obj = self.tx.to_pulsar(data)
+        assert len(obj.metadata) == 1
+        assert obj.metadata[0].s.iri == "http://example.org/s"
+
+    def test_none_metadata_handled(self):
+        data = {"metadata": None}
+        obj = self.tx.to_pulsar(data)
+        assert obj.metadata == []
+
+    def test_empty_tags_preserved(self):
+        data = {"tags": []}
+        obj = self.tx.to_pulsar(data)
+        wire = self.tx.from_pulsar(obj)
+        assert wire["tags"] == []
+
+    def test_falsy_fields_omitted_from_wire(self):
+        """Empty string fields should be omitted from wire format."""
+        obj = DocumentMetadata(id="", time=0, user="")
+        wire = self.tx.from_pulsar(obj)
+        assert "id" not in wire
+        assert "user" not in wire
+
+
+# ---------------------------------------------------------------------------
+# ProcessingMetadata translator
+# ---------------------------------------------------------------------------
+
+class TestProcessingMetadataTranslator:
+
+    def setup_method(self):
+        self.tx = ProcessingMetadataTranslator()
+
+    def test_full_round_trip(self):
+        data = {
+            "id": "proc-1",
+            "document-id": "doc-123",
+            "time": 1710000000,
+            "flow": "default",
+            "user": "alice",
+            "collection": "my-collection",
+            "tags": ["tag1"],
+        }
+        obj = self.tx.to_pulsar(data)
+        assert obj.id == "proc-1"
+        assert obj.document_id == "doc-123"
+        assert obj.flow == "default"
+        assert obj.user == "alice"
+        assert obj.collection == "my-collection"
+        assert obj.tags == ["tag1"]
+
+        wire = self.tx.from_pulsar(obj)
+        assert wire["id"] == "proc-1"
+        assert wire["document-id"] == "doc-123"
+        assert wire["user"] == "alice"
+        assert wire["collection"] == "my-collection"
+
+    def test_missing_fields_use_defaults(self):
+        obj = self.tx.to_pulsar({})
+        assert obj.id is None
+        assert obj.user is None
+        assert obj.collection is None
+
+    def test_tags_none_omitted(self):
+        obj = ProcessingMetadata(tags=None)
+        wire = self.tx.from_pulsar(obj)
+        assert "tags" not in wire
+
+    def test_tags_empty_list_preserved(self):
+        obj = ProcessingMetadata(tags=[])
+        wire = self.tx.from_pulsar(obj)
+        assert wire["tags"] == []
+
+    def test_user_and_collection_preserved(self):
+        """Core pipeline routing fields must survive round-trip."""
+        data = {"user": "bob", "collection": "research"}
+        obj = self.tx.to_pulsar(data)
+        wire = self.tx.from_pulsar(obj)
+        assert wire["user"] == "bob"
+        assert wire["collection"] == "research"