test: add document hashing unit tests and clean up conftest mocks

surfsense_backend/app/indexing_pipeline/document_hashing.py

@@ -0,0 +1,13 @@
+import hashlib
+
+from app.indexing_pipeline.connector_document import ConnectorDocument
+
+
+def compute_unique_identifier_hash(doc: ConnectorDocument) -> str:
+    combined = f"{doc.document_type.value}:{doc.unique_id}:{doc.search_space_id}"
+    return hashlib.sha256(combined.encode("utf-8")).hexdigest()
+
+
+def compute_content_hash(doc: ConnectorDocument) -> str:
+    combined = f"{doc.search_space_id}:{doc.source_markdown}"
+    return hashlib.sha256(combined.encode("utf-8")).hexdigest()