fix(orchestrator): Apply refinements from code review

backend/tests/test_review_fix_summary.py

@@ -0,0 +1,51 @@
+import pytest
+from ea_chatbot.graph.workers.data_analyst.mapping import merge_worker_output as merge_analyst
+from ea_chatbot.graph.workers.researcher.mapping import merge_researcher_output as merge_researcher
+from ea_chatbot.graph.workers.data_analyst.state import WorkerState as AnalystState
+from ea_chatbot.graph.workers.researcher.state import WorkerState as ResearcherState
+
+def test_analyst_merge_updates_summary():
+    """Verify that analyst merge updates the global summary."""
+    worker_state = AnalystState(
+        result="Actual Worker Result",
+        messages=[],
+        task="test",
+        iterations=1,
+        vfs_state={},
+        plots=[]
+    )
+    
+    updates = merge_analyst(worker_state)
+    assert "summary" in updates
+    assert updates["summary"] == "Actual Worker Result"
+
+def test_researcher_merge_updates_summary():
+    """Verify that researcher merge updates the global summary."""
+    worker_state = ResearcherState(
+        result="Actual Research Result",
+        messages=[],
+        task="test",
+        iterations=1,
+        queries=[],
+        raw_results=[]
+    )
+    
+    updates = merge_researcher(worker_state)
+    assert "summary" in updates
+    assert updates["summary"] == "Actual Research Result"
+
+def test_merge_handles_none_result():
+    """Verify that merge functions handle None results gracefully."""
+    worker_state = AnalystState(
+        result=None,
+        messages=[],
+        task="test",
+        iterations=1,
+        vfs_state={},
+        plots=[]
+    )
+    
+    updates = merge_analyst(worker_state)
+    assert updates["summary"] is not None
+    assert isinstance(updates["messages"][0].content, str)
+    assert len(updates["messages"][0].content) > 0