mock rpc connection

runtime/src/main/java/org/capnproto/IncomingRpcMessage.java

@@ -6,5 +6,7 @@ public interface IncomingRpcMessage {
 
     AnyPointer.Reader getBody();
 
-    List<Integer> getAttachedFds();
+    default List<Integer> getAttachedFds() {
+        return List.of();
+    }
 }

runtime/src/main/java/org/capnproto/OutgoingRpcMessage.java

@@ -6,7 +6,8 @@ public interface OutgoingRpcMessage {
 
     AnyPointer.Builder getBody();
 
-    void setFds(List<Integer> fds);
+    default void setFds(List<Integer> fds) {
+    }
 
     void send();
 

runtime/src/main/java/org/capnproto/RpcState.java

@@ -83,6 +83,12 @@ final class RpcState {
     };
 
     private final HashMap<ClientHook, Integer> exportsByCap = new HashMap<>();
+    private final VatNetwork.Connection connection;
+
+
+    RpcState(VatNetwork.Connection connection) {
+        this.connection = connection;
+    }
 
     void handleMessage(IncomingRpcMessage message) {
         var reader = message.getBody().getAs(RpcProtocol.Message.factory);

runtime/src/test/java/org/capnproto/RpcStateTest.java

@@ -1,13 +1,81 @@
 package org.capnproto;
 
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
 import org.junit.Test;
 
+import java.util.ArrayDeque;
+import java.util.Queue;
+import java.util.concurrent.CompletableFuture;
+
 import static org.junit.Assert.*;
 
 public class RpcStateTest {
 
+    class TestMessage implements IncomingRpcMessage {
+
+        MessageBuilder builder = new MessageBuilder();
+
+        @Override
+        public AnyPointer.Reader getBody() {
+            return builder.getRoot(AnyPointer.factory).asReader();
+        }
+    }
+
+    class TestConnection implements VatNetwork.Connection {
+
+        @Override
+        public OutgoingRpcMessage newOutgoingMessage(int firstSegmentWordSize) {
+            var message = new MessageBuilder();
+
+            return new OutgoingRpcMessage() {
+                @Override
+                public AnyPointer.Builder getBody() {
+                    return message.getRoot(AnyPointer.factory);
+                }
+
+                @Override
+                public void send() {
+                    sent.add(this);
+                }
+
+                @Override
+                public int sizeInWords() {
+                    return 0;
+                }
+            };
+        }
+
+        @Override
+        public CompletableFuture<IncomingRpcMessage> receiveIncomingMessage() {
+            return null;
+        }
+    }
+
+    TestConnection connection;
+    RpcState rpc;
+    final Queue<OutgoingRpcMessage> sent = new ArrayDeque<>();
+
+    @Before
+    public void setUp() throws Exception {
+        connection = new TestConnection();
+        rpc = new RpcState(connection);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        connection = null;
+        rpc = null;
+        sent.clear();
+    }
+
     @Test
     public void handleUnimplemented() {
+        var msg = new TestMessage();
+        msg.builder.getRoot(RpcProtocol.Message.factory).initUnimplemented();
+        rpc.handleMessage(msg);
+        Assert.assertTrue(sent.isEmpty());
     }
 
     @Test
@@ -37,4 +105,5 @@ public class RpcStateTest {
     @Test
     public void handleDisembargo() {
     }
+
 }