Figured out why Security232Test.commonsCollections1 was being skipped 10% of the time.

test/src/test/java/jenkins/security/Security232Test.java

@@ -28,10 +28,10 @@ import java.rmi.activation.ActivationInstantiator;
 import java.rmi.server.ObjID;
 import java.rmi.server.RemoteObject;
 import java.rmi.server.UnicastRemoteObject;
+import java.util.Collections;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import javax.net.SocketFactory;
-import static jenkins.security.security218.Payload.CommonsCollections1;
 import jenkins.security.security218.ysoserial.payloads.CommonsCollections1;
 import jenkins.security.security218.ysoserial.payloads.ObjectPayload;
 import static org.junit.Assert.*;
@@ -59,6 +59,8 @@ public class Security232Test {
 
     @Test
     public void commonsCollections1() throws Exception {
+        r.jenkins.setAgentProtocols(Collections.singleton("CLI-connect")); // override CliProtocol.OPT_IN
+
         File pwned = new File(r.jenkins.getRootDir(), "pwned");
 
         int jrmpPort = 12345;