Fallback to hostname command to check hostname

In metadata test, to make new CI happy.

Author: acogoluegnes

src/test/java/com/rabbitmq/stream/Host.java

@@ -55,6 +55,11 @@ private static Process executeCommand(String command) throws IOException {
     return pr;
   }
 
+  public static String hostname() throws IOException {
+    Process process = executeCommand("hostname");
+    return capture(process.getInputStream()).trim();
+  }
+
   private static int waitForExitValue(Process pr) {
     while (true) {
       try {

src/test/java/com/rabbitmq/stream/impl/MetadataTest.java

@@ -20,6 +20,7 @@
 import com.rabbitmq.stream.Constants;
 import com.rabbitmq.stream.Host;
 import com.rabbitmq.stream.impl.Client.Broker;
+import java.io.IOException;
 import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.util.*;
@@ -144,7 +145,11 @@ static String hostname() {
     try {
       return InetAddress.getLocalHost().getHostName();
     } catch (UnknownHostException e) {
-      throw new RuntimeException(e);
+      try {
+        return Host.hostname();
+      } catch (IOException ex) {
+        throw new RuntimeException(ex);
+      }
     }
   }
 }