test: Added unit tests for the rag, completions and prompt, macros, vault, and functions/tool usage

docs/testing/plans/12-rag.md

@@ -1,16 +1,32 @@
 # Test Plan: RAG
 
 ## Behaviors to test
-- [ ] Rag::init creates new RAG with embedding model
-- [ ] Rag::load loads existing RAG from disk
-- [ ] Rag::create builds vector store from documents
-- [ ] Rag::refresh_document_paths updates document list
-- [ ] RAG search returns relevant embeddings
-- [ ] RAG template formats context + sources + input
-- [ ] Reranker model applied when configured
-- [ ] top_k controls number of results
-- [ ] RAG sources tracked for .sources command
-- [ ] exit_rag clears RAG from context
+- [ ] Rag::init creates new RAG with embedding model (requires LLM client)
+- [ ] Rag::load loads existing RAG from disk (requires filesystem)
+- [ ] Rag::create builds vector store from documents (requires embedding model)
+- [ ] Rag::refresh_document_paths updates document list (requires filesystem)
+- [ ] RAG search returns relevant embeddings (requires embedding model)
+- [x] RAG template contains required placeholders
+- [ ] Reranker model applied when configured (requires LLM client)
+- [ ] top_k controls number of results (requires embedding model)
+- [ ] RAG sources tracked for .sources command (requires full Rag struct)
+- [x] exit_rag clears RAG from context (tested in iteration 8)
+
+## Additional behaviors tested
+
+- [x] DocumentId: new/split round-trip, zero/zero, large values
+- [x] DocumentId: Debug format ("file-doc"), equality, inequality, ordering
+- [x] RagDocument: new with content, default empty
+- [x] RagData: new sets all defaults, empty collections
+- [x] RagData::get: returns document, None for missing file, None for missing doc index
+- [x] RagData::del: removes files + associated vectors, noop for nonexistent
+- [x] RagData::add: inserts files, vectors, updates next_file_id
+- [x] RagData::build_bm25: empty data returns no results
+- [x] RagData::build_bm25: finds documents by keyword (BM25 ranking)
+- [x] RAG_TEMPLATE: contains __CONTEXT__, __SOURCES__, __INPUT__
+- [x] get_separators: Rust/Python/Markdown return language-specific
+- [x] get_separators: unknown extension returns defaults
+- [x] get_separators: all 22 known extensions have language-specific separators
 
 ## Old code reference
 - `src/rag/mod.rs` — Rag struct and methods