Validate demotion successor against peer map

tests/test-demote-prepare.py

@@ -37,7 +37,13 @@ runtime_state = {
 }
 
 result = plugin.demote_prepare(
-    {"PACEMAKER_NODE_NAME": "david-eve"},
+    {
+        "PACEMAKER_NODE_NAME": "david-eve",
+        "PG_REPLICATION_PEERS": (
+            "david-prodesk=192.168.1.4:5432,"
+            "david-eve=192.168.1.3:5432"
+        ),
+    },
     runtime_state,
     {},
 )
@@ -47,6 +53,9 @@ assert result["ready"] is False
 assert result["identity_validated"] is True
 assert result["reason"] == "database_checks_pending"
 assert result["checks"]["database_checks"] is False
+assert result["checks"]["peer_map"] is True
+assert result["successor_host"] == "192.168.1.4"
+assert result["successor_port"] == 5432
 assert result["mutation"] is False
 assert result["successor_node"] == "david-prodesk"
 print("valid_prepare            accepted")
@@ -90,3 +99,28 @@ print("missing_successor        rejected")
 
 print()
 print("DEMOTE_PREPARE_TEST_PASS=1")
+
+result = plugin.demote_prepare(
+    {
+        "PACEMAKER_NODE_NAME": "david-eve",
+        "PG_REPLICATION_PEERS": (
+            "david-macbookpro=192.168.1.5:5432"
+        ),
+    },
+    {
+        "postgresql": {
+            "notification": {
+                "type": "pre",
+                "operation": "demote",
+                "demote_uname": "david-eve",
+                "promote_uname": "david-prodesk",
+                "received_at": time.time(),
+            },
+        },
+    },
+    {},
+)
+
+assert result["ocf_rc"] == 1
+assert result["reason"] == "successor_not_configured"
+print("unconfigured_successor  rejected")