feat: add engine identity module (FQDN resolution via node.env, hostname fallback)

tests/test_identity.py

@@ -0,0 +1,42 @@
+# tests/test_identity.py
+import os, tempfile, unittest
+from engine.identity import resolve, Node
+
+class TestIdentity(unittest.TestCase):
+    def _envfile(self, text, dirname=None):
+        d = tempfile.mkdtemp()
+        if dirname:
+            d = os.path.join(d, dirname)
+            os.makedirs(d)
+        with open(os.path.join(d, "node.env"), "w") as f:
+            f.write(text)
+        return d
+
+    def test_fqdn_is_source_of_truth(self):
+        repo = self._envfile("APEX_CLUSTER=a1\nAPEX_SUBNET=198.18.11.0/24\n")
+        n, warns = resolve("daedalus.a1.apex.ermnvldmr.com", repo)
+        self.assertEqual((n.name, n.cluster, n.subnet), ("daedalus", "a1", "198.18.11.0/24"))
+        self.assertEqual(warns, [])
+
+    def test_cluster_drift_warns_hostname_wins(self):
+        repo = self._envfile("APEX_CLUSTER=a9\nAPEX_SUBNET=198.18.11.0/24\n")
+        n, warns = resolve("daedalus.a1.apex.ermnvldmr.com", repo)
+        self.assertEqual(n.cluster, "a1")           # hostname wins
+        self.assertTrue(any("drift" in w.lower() for w in warns))
+
+    def test_fallback_when_fqdn_not_apex_shaped(self):
+        # repo dir basename carries the node name in fallback (real host layout:
+        # $HOME/morpheus.apex.ermnvldmr.com)
+        repo = self._envfile("APEX_CLUSTER=a2\nAPEX_SUBNET=198.18.13.0/24\n",
+                             dirname="morpheus.apex.ermnvldmr.com")
+        n, warns = resolve("build-laptop", repo)
+        self.assertEqual((n.name, n.cluster, n.subnet), ("morpheus", "a2", "198.18.13.0/24"))
+        self.assertTrue(any("fqdn" in w.lower() for w in warns))
+
+    def test_missing_subnet_is_error(self):
+        repo = self._envfile("APEX_CLUSTER=a1\n")
+        with self.assertRaises(SystemExit):
+            resolve("daedalus.a1.apex.ermnvldmr.com", repo)
+
+if __name__ == "__main__":
+    unittest.main()