fleetd #567: assert inspect closes probe channel

fleetd/src/test/java/dev/ltms/fleet/msg/LeadMailboxTest.java

@@ -19,6 +19,7 @@ import java.util.concurrent.atomic.AtomicLong;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -207,6 +208,31 @@ class LeadMailboxTest {
         }
     }
 
+    /**
+     * {@link LeadMailbox#inspect} opens a third channel after the mailbox's consume and publish
+     * channels. Limit this connection to three channels, then require a replacement channel after
+     * the successful inspect. If inspect leaves its probe open, the broker refuses that replacement.
+     */
+    @Test
+    void inspectClosesItsSuccessfulProbeChannel() throws Exception {
+        var factory = LeadMailbox.connectionFactory(uri());
+        factory.setRequestedChannelMax(3);
+        Connection connection = factory.newConnection();
+        try (LeadMailbox mailbox = new LeadMailbox(connection, coordId("lead-inspect-probe-close"))) {
+            LeadChannel.MailboxState state = mailbox.inspect(mailbox.selfCoordId());
+            assertTrue(state.exists(), "the owned mailbox must be found before checking the probe channel");
+
+            Channel replacement = connection.createChannel();
+            assertNotNull(replacement,
+                    "inspect must close its successful probe channel; the replacement channel was null");
+            try {
+                assertTrue(replacement.isOpen(), "the replacement channel must be open after inspect returns");
+            } finally {
+                replacement.close();
+            }
+        }
+    }
+
     /**
      * fleetd #440: {@code heldDurable()} must be derived from what {@link LeadMailbox#own} actually
      * did against the real broker — a durable queue declare plus a manual-ack consumer — not a