feat: Implement multi-node support with MQTT and mDNS for service discovery and coordination

castle-api/tests/test_mqtt.py

@@ -0,0 +1,96 @@
+"""Tests for MQTT client serialization logic."""
+
+import json
+
+from castle_core.registry import DeployedComponent, NodeConfig, NodeRegistry
+
+from castle_api.mqtt_client import _json_to_registry, _registry_to_json
+
+
+def _make_registry() -> NodeRegistry:
+    return NodeRegistry(
+        node=NodeConfig(hostname="tower", castle_root="/data/repos/castle", gateway_port=9000),
+        deployed={
+            "my-svc": DeployedComponent(
+                runner="python",
+                run_cmd=["uv", "run", "my-svc"],
+                env={"PORT": "9001", "SECRET_KEY": "super-secret"},
+                description="My service",
+                category="service",
+                port=9001,
+                health_path="/health",
+                proxy_path="/my-svc",
+                managed=True,
+            ),
+            "my-job": DeployedComponent(
+                runner="command",
+                run_cmd=["my-job"],
+                category="job",
+                schedule="0 2 * * *",
+            ),
+        },
+    )
+
+
+class TestRegistrySerialization:
+    """Round-trip serialization of NodeRegistry to/from JSON."""
+
+    def test_round_trip(self) -> None:
+        original = _make_registry()
+        json_str = _registry_to_json(original)
+        restored = _json_to_registry(json_str)
+
+        assert restored.node.hostname == "tower"
+        assert restored.node.gateway_port == 9000
+
+    def test_deployed_components_preserved(self) -> None:
+        original = _make_registry()
+        restored = _json_to_registry(_registry_to_json(original))
+
+        assert "my-svc" in restored.deployed
+        svc = restored.deployed["my-svc"]
+        assert svc.runner == "python"
+        assert svc.port == 9001
+        assert svc.health_path == "/health"
+        assert svc.proxy_path == "/my-svc"
+        assert svc.managed is True
+
+    def test_job_fields_preserved(self) -> None:
+        original = _make_registry()
+        restored = _json_to_registry(_registry_to_json(original))
+
+        assert "my-job" in restored.deployed
+        job = restored.deployed["my-job"]
+        assert job.runner == "command"
+        assert job.schedule == "0 2 * * *"
+        assert job.category == "job"
+
+    def test_optional_fields_omitted(self) -> None:
+        """Fields like port, health_path are None when not set."""
+        reg = NodeRegistry(
+            node=NodeConfig(hostname="minimal"),
+            deployed={
+                "bare": DeployedComponent(runner="command", run_cmd=["bare"]),
+            },
+        )
+        restored = _json_to_registry(_registry_to_json(reg))
+        bare = restored.deployed["bare"]
+        assert bare.port is None
+        assert bare.health_path is None
+        assert bare.proxy_path is None
+        assert bare.schedule is None
+        assert bare.managed is False
+
+    def test_no_secrets_in_payload(self) -> None:
+        """env vars, run_cmd, and castle_root must not appear in MQTT payload."""
+        original = _make_registry()
+        json_str = _registry_to_json(original)
+        data = json.loads(json_str)
+
+        # No castle_root in node
+        assert "castle_root" not in data["node"]
+
+        # No env or run_cmd in any component
+        for name, comp in data["deployed"].items():
+            assert "env" not in comp, f"{name} has env in MQTT payload"
+            assert "run_cmd" not in comp, f"{name} has run_cmd in MQTT payload"