Fix coverage

haiku_rag_slim/haiku/rag/tools/qa.py

@@ -267,9 +267,7 @@ def create_qa_toolset(
         if client_snapshot is not None and tool_context is not None:
             new_snapshot = tool_context.build_state_snapshot()
             state_event = compute_combined_state_delta(
-                client_snapshot,
-                new_snapshot,
-                state_key=state_key,
+                client_snapshot, new_snapshot, state_key=state_key
             )
 
             if state_event is not None:

tests/agents/chat/test_chat_agent.py

@@ -1419,3 +1419,209 @@ async def test_summarization_task_cleanup_on_completion():
 
     # Task should be cleaned up
     assert key not in _summarization_tasks
+
+
+@pytest.mark.asyncio
+async def test_ask_tool_returns_qa_result_when_no_state_delta(temp_db_path):
+    """Test ask tool falls through to QAResult when state delta is empty.
+
+    When run_qa_core produces no state changes (client_snapshot == new_snapshot),
+    compute_combined_state_delta returns None and the tool returns QAResult directly.
+    """
+    from unittest.mock import AsyncMock, patch
+
+    from pydantic_ai import Agent
+    from pydantic_ai.models.test import TestModel
+
+    from haiku.rag.tools.models import QAResult
+    from haiku.rag.tools.qa import create_qa_toolset
+
+    async with HaikuRAG(temp_db_path, create=True) as client:
+        context = ToolContext()
+        prepare_chat_context(context, features=["search", "qa"])
+        context.state_key = AGUI_STATE_KEY
+
+        deps = ChatDeps(config=Config, client=client, tool_context=context)
+        toolset = create_qa_toolset(Config)
+        agent = Agent(
+            TestModel(call_tools=["ask"]),
+            deps_type=ChatDeps,
+            toolsets=[toolset],  # ty: ignore[invalid-argument-type]
+        )
+
+        # Mock run_qa_core to return a result WITHOUT modifying any state.
+        # Since client_snapshot == new_snapshot, the delta is None.
+        mock_result = QAResult(
+            question="test", answer="The answer", confidence=0.9, citations=[]
+        )
+        with patch(
+            "haiku.rag.tools.qa.run_qa_core",
+            new_callable=AsyncMock,
+            return_value=mock_result,
+        ):
+            result = await agent.run(
+                "test question",
+                deps=deps,  # ty: ignore[invalid-argument-type]
+            )
+
+        # The tool should have returned the QAResult (not a ToolReturn)
+        assert "The answer" in result.output
+
+
+@pytest.mark.asyncio
+async def test_ask_tool_delta_without_citations(temp_db_path):
+    """Test ask tool emits StateDeltaEvent without citation sources when citations are empty.
+
+    When the QA result has no citations but state DID change,
+    the tool returns a ToolReturn with a delta but no 'Sources:' line.
+    """
+    from unittest.mock import AsyncMock, patch
+
+    from pydantic_ai import Agent
+    from pydantic_ai.models.test import TestModel
+
+    from haiku.rag.tools.models import QAResult
+    from haiku.rag.tools.qa import (
+        QA_SESSION_NAMESPACE,
+        QASessionState,
+        create_qa_toolset,
+    )
+
+    async with HaikuRAG(temp_db_path, create=True) as client:
+        context = ToolContext()
+        prepare_chat_context(context, features=["search", "qa"])
+        context.state_key = AGUI_STATE_KEY
+
+        deps = ChatDeps(config=Config, client=client, tool_context=context)
+        toolset = create_qa_toolset(Config)
+        agent = Agent(
+            TestModel(call_tools=["ask"]),
+            deps_type=ChatDeps,
+            toolsets=[toolset],  # ty: ignore[invalid-argument-type]
+        )
+
+        mock_result = QAResult(
+            question="test", answer="No citations answer", confidence=0.9, citations=[]
+        )
+
+        async def mock_qa_core(*args, **kwargs):
+            # Simulate state mutation (qa_history entry) but no citations
+            ctx = kwargs.get("context")
+            if ctx is not None:
+                qa_state = ctx.get(QA_SESSION_NAMESPACE, QASessionState)
+                if qa_state is not None:
+                    qa_state.qa_history.append(
+                        QAHistoryEntry(question="test", answer="No citations answer")
+                    )
+            return mock_result
+
+        with patch(
+            "haiku.rag.tools.qa.run_qa_core",
+            new_callable=AsyncMock,
+            side_effect=mock_qa_core,
+        ):
+            result = await agent.run(
+                "test question",
+                deps=deps,  # ty: ignore[invalid-argument-type]
+            )
+
+        # Should have the answer but NO "Sources:" line
+        assert "No citations answer" in result.output
+        assert "Sources:" not in result.output
+
+        # Should have emitted a StateDeltaEvent (qa_history changed)
+        state = extract_state_from_result(result)
+        assert state is not None
+        assert len(state.get("qa_history", [])) > 0
+
+
+@pytest.mark.asyncio
+async def test_ask_tool_delta_with_citations(temp_db_path):
+    """Test ask tool emits StateDeltaEvent with 'Sources:' line when citations are present.
+
+    When the QA result has citations and state changed, the tool returns
+    a ToolReturn with a delta and appended 'Sources: [1] [2]' line.
+    """
+    from unittest.mock import AsyncMock, patch
+
+    from pydantic_ai import Agent
+    from pydantic_ai.models.test import TestModel
+
+    from haiku.rag.tools.models import QAResult
+    from haiku.rag.tools.qa import (
+        QA_SESSION_NAMESPACE,
+        QASessionState,
+        create_qa_toolset,
+    )
+
+    async with HaikuRAG(temp_db_path, create=True) as client:
+        context = ToolContext()
+        prepare_chat_context(context, features=["search", "qa"])
+        context.state_key = AGUI_STATE_KEY
+
+        deps = ChatDeps(config=Config, client=client, tool_context=context)
+        toolset = create_qa_toolset(Config)
+        agent = Agent(
+            TestModel(call_tools=["ask"]),
+            deps_type=ChatDeps,
+            toolsets=[toolset],  # ty: ignore[invalid-argument-type]
+        )
+
+        citations = [
+            Citation(
+                index=1,
+                document_id="doc-1",
+                chunk_id="chunk-a",
+                document_uri="test.md",
+                document_title="Test",
+                content="content",
+            ),
+            Citation(
+                index=2,
+                document_id="doc-1",
+                chunk_id="chunk-b",
+                document_uri="test.md",
+                document_title="Test",
+                content="content",
+            ),
+        ]
+        mock_result = QAResult(
+            question="test",
+            answer="Cited answer",
+            confidence=0.95,
+            citations=citations,
+        )
+
+        async def mock_qa_core(*args, **kwargs):
+            ctx = kwargs.get("context")
+            if ctx is not None:
+                qa_state = ctx.get(QA_SESSION_NAMESPACE, QASessionState)
+                if qa_state is not None:
+                    qa_state.qa_history.append(
+                        QAHistoryEntry(
+                            question="test",
+                            answer="Cited answer",
+                            citations=citations,
+                        )
+                    )
+            return mock_result
+
+        with patch(
+            "haiku.rag.tools.qa.run_qa_core",
+            new_callable=AsyncMock,
+            side_effect=mock_qa_core,
+        ):
+            result = await agent.run(
+                "test question",
+                deps=deps,  # ty: ignore[invalid-argument-type]
+            )
+
+        # Should have the answer WITH "Sources:" line
+        assert "Cited answer" in result.output
+        assert "Sources:" in result.output
+        assert "[1]" in result.output
+        assert "[2]" in result.output
+
+        # Should have emitted a StateDeltaEvent
+        state = extract_state_from_result(result)
+        assert state is not None