test: add design state, mock orchestrator, and orchestrator tests

fix: part name regex in design_state.py — {5,40?} → {5,40}? (lazy quantifier)
- test_design_state.py: 12 tests for DesignState model + extract_decisions
- test_mock_orchestrator.py: 10 tests for MockChatBackend routing + responses
- test_single_call_orchestrator.py: 8 tests with fake LLM backend

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

agents/design_state.py

@@ -164,7 +164,7 @@ def extract_decisions(
     # Extract part name from user message if not set
     if not state.part_name and user_message:
         name_patterns = [
-            r'(?:need|want|design|make|create)\s+(?:a|an)\s+(.{5,40?})\s*(?:with|for|that|,|$)',
+            r'(?:need|want|design|make|create)\s+(?:a|an)\s+(.{5,40}?)\s*(?:with|for|that|,|$)',
         ]
         for pattern in name_patterns:
             match = re.search(pattern, user_message, re.IGNORECASE)

tests/test_design_state.py

@@ -0,0 +1,90 @@
+"""Tests for agents/design_state.py — state tracking and decision extraction."""
+
+from agents.design_state import DesignState, extract_decisions
+
+
+class TestDesignState:
+    def test_empty_render(self):
+        state = DesignState()
+        assert state.render() == ""
+
+    def test_render_with_fields(self):
+        state = DesignState(
+            part_name="bracket",
+            material="aluminum 6061",
+            dimensions={"width": 60.0, "height": 40.0},
+        )
+        rendered = state.render()
+        assert "bracket" in rendered
+        assert "aluminum 6061" in rendered
+        assert "width=60.0mm" in rendered
+
+    def test_render_features(self):
+        state = DesignState(features=["4x M6 holes", "fillet"])
+        rendered = state.render()
+        assert "4x M6 holes" in rendered
+
+    def test_render_decisions_capped_at_5(self):
+        state = DesignState(decisions=[f"decision {i}" for i in range(10)])
+        rendered = state.render()
+        assert "decision 9" in rendered
+        assert "decision 4" not in rendered
+
+
+class TestExtractDecisions:
+    def test_extracts_material(self):
+        responses = [
+            {"agent_id": "engineering", "message": "I recommend aluminum 6061 for this application."}
+        ]
+        state = extract_decisions(responses, DesignState())
+        assert "aluminum" in state.material.lower()
+
+    def test_extracts_dimensions_from_user(self):
+        responses = []
+        state = extract_decisions(responses, DesignState(), user_message="Make it 60mm wide and 40mm high")
+        assert state.dimensions.get("width") == 60.0
+        assert state.dimensions.get("height") == 40.0
+
+    def test_extracts_fastener_features(self):
+        responses = [
+            {"agent_id": "engineering", "message": "I'll add 4x M6 clearance holes for mounting."}
+        ]
+        state = extract_decisions(responses, DesignState())
+        assert any("M6" in f for f in state.features)
+
+    def test_extracts_axis_recommendation(self):
+        responses = [
+            {"agent_id": "cnc", "message": "This part needs 5-axis machining due to the undercut."}
+        ]
+        state = extract_decisions(responses, DesignState())
+        assert "5-axis" in state.axis_recommendation
+
+    def test_extracts_part_name(self):
+        responses = []
+        state = extract_decisions(responses, DesignState(), user_message="I need a servo bracket with M4 holes")
+        assert "servo bracket" in state.part_name.lower()
+
+    def test_preserves_existing_state(self):
+        existing = DesignState(material="steel", dimensions={"width": 50.0})
+        responses = [
+            {"agent_id": "engineering", "message": "Height should be 30mm."}
+        ]
+        updated = extract_decisions(responses, existing, user_message="add height")
+        assert updated.material == "steel"
+        assert updated.dimensions.get("width") == 50.0
+
+    def test_extracts_decisions_from_agreement(self):
+        responses = [
+            {"agent_id": "design", "message": "I'd recommend an L-bracket form factor for this."}
+        ]
+        state = extract_decisions(responses, DesignState())
+        assert len(state.decisions) > 0
+
+    def test_no_duplicate_features(self):
+        existing = DesignState(features=["4x M6 holes"])
+        responses = [
+            {"agent_id": "engineering", "message": "The 4x M6 holes are properly specified."}
+        ]
+        updated = extract_decisions(responses, existing)
+        m6_count = sum(1 for f in updated.features if "M6" in f)
+        assert m6_count == 1

tests/test_mock_orchestrator.py

@@ -0,0 +1,87 @@
+"""Tests for agents/orchestrator.py — MockChatBackend and helpers."""
+
+from agents.orchestrator import MockChatBackend, _format_response
+from agents.definitions import AGENTS, AGENT_COLORS, AGENT_NAMES, AGENT_AVATARS
+
+
+class TestFormatResponse:
+    def test_returns_all_fields(self):
+        resp = _format_response("design", "Hello")
+        assert resp["agent_id"] == "design"
+        assert resp["agent_name"] == AGENT_NAMES["design"]
+        assert resp["message"] == "Hello"
+        assert resp["color"] == AGENT_COLORS["design"]
+        assert resp["avatar"] == AGENT_AVATARS["design"]
+        assert resp["code"] is None
+
+    def test_includes_code(self):
+        resp = _format_response("cad", "Done.", code="result = cq.Workplane().box(10,10,10)")
+        assert resp["code"] == "result = cq.Workplane().box(10,10,10)"
+
+
+class TestMockChatBackend:
+    def test_response_shape(self, tmp_output_dir):
+        mock = MockChatBackend(output_dir=tmp_output_dir)
+        result = mock.chat_turn("I need a bracket", history=[])
+        assert "responses" in result
+        assert "preview" in result
+        assert "design_state" in result
+        assert isinstance(result["responses"], list)
+        assert len(result["responses"]) > 0
+
+    def test_bracket_routes_to_design(self, tmp_output_dir):
+        mock = MockChatBackend(output_dir=tmp_output_dir)
+        result = mock.chat_turn("Design a mounting bracket", history=[])
+        agent_ids = [r["agent_id"] for r in result["responses"]]
+        assert "design" in agent_ids
+
+    def test_mention_overrides_routing(self, tmp_output_dir):
+        mock = MockChatBackend(output_dir=tmp_output_dir)
+        result = mock.chat_turn(
+            "What do you think?",
+            history=[],
+            mentions=["cnc"],
+        )
+        agent_ids = [r["agent_id"] for r in result["responses"]]
+        assert agent_ids == ["cnc"]
+
+    def test_cad_mention_generates_code(self, tmp_output_dir):
+        mock = MockChatBackend(output_dir=tmp_output_dir)
+        result = mock.chat_turn(
+            "Generate a 50mm cube",
+            history=[],
+            mentions=["cad"],
+        )
+        agent_ids = [r["agent_id"] for r in result["responses"]]
+        assert "cad" in agent_ids
+        cad_resp = next(r for r in result["responses"] if r["agent_id"] == "cad")
+        assert cad_resp["code"] is not None
+        assert "result" in cad_resp["code"]
+
+    def test_design_state_updated(self, tmp_output_dir):
+        mock = MockChatBackend(output_dir=tmp_output_dir)
+        result = mock.chat_turn(
+            "Make it 60mm wide in aluminum",
+            history=[],
+        )
+        ds = result["design_state"]
+        assert isinstance(ds, dict)
+
+    def test_engineering_keywords_trigger_engineering(self, tmp_output_dir):
+        mock = MockChatBackend(output_dir=tmp_output_dir)
+        result = mock.chat_turn("Use M6 bolts with 3mm wall thickness", history=[])
+        agent_ids = [r["agent_id"] for r in result["responses"]]
+        assert "engineering" in agent_ids
+
+    def test_cnc_keywords_trigger_cnc(self, tmp_output_dir):
+        mock = MockChatBackend(output_dir=tmp_output_dir)
+        result = mock.chat_turn("Can this be machined on a CNC mill?", history=[])
+        agent_ids = [r["agent_id"] for r in result["responses"]]
+        assert "cnc" in agent_ids
+
+    def test_generic_message_default_agents(self, tmp_output_dir):
+        mock = MockChatBackend(output_dir=tmp_output_dir)
+        result = mock.chat_turn("Hello there", history=[])
+        agent_ids = [r["agent_id"] for r in result["responses"]]
+        assert "design" in agent_ids
+        assert "engineering" in agent_ids