diff --git a/agents-flex-core/src/test/java/com/agentsflex/core/test/chain/ChainAsyncStringTest.java b/agents-flex-core/src/test/java/com/agentsflex/core/test/chain/ChainAsyncStringTest.java
new file mode 100644
index 0000000..b2199e1
--- /dev/null
+++ b/agents-flex-core/src/test/java/com/agentsflex/core/test/chain/ChainAsyncStringTest.java
@@ -0,0 +1,107 @@
+package com.agentsflex.core.test.chain;
+
+import com.agentsflex.core.chain.*;
+import com.agentsflex.core.util.Maps;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class ChainAsyncStringTest {
+
+    @Test
+    public void test() {
+
+        System.out.println("start: "+ Thread.currentThread().getId());
+
+        Chain chain = new Chain();
+
+        TestNode a = new TestNode();
+        a.setId("a");
+        chain.addNode(a);
+
+        /// //bbbbb
+        TestNode b = new TestNode(){
+            @Override
+            protected Map<String, Object> execute(Chain chain) {
+                System.out.println("b: "+ Thread.currentThread().getId());
+                try {
+                    Thread.sleep(2000);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+                System.out.println("b");
+                return Maps.of();
+            }
+        };
+        b.setId("b");
+        b.setAsync(true);
+
+        chain.addNode(b);
+
+
+        /// //////cccccc
+        TestNode c = new TestNode(){
+            @Override
+            protected Map<String, Object> execute(Chain chain) {
+                System.out.println("c: "+ Thread.currentThread().getId());
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+                System.out.println("c");
+                return Maps.of();
+            }
+        };
+        c.setId("c");
+        c.setAsync(true);
+        chain.addNode(c);
+
+
+        /// /////dddd
+        TestNode d = new TestNode() {
+            @Override
+            protected Map<String, Object> execute(Chain chain) {
+                System.out.println("d: "+ Thread.currentThread().getId());
+                return Maps.of();
+            }
+        };
+        d.setId("d");
+
+        d.setCondition(new JsCodeCondition("_context.isUpstreamFullyExecuted()"));
+        chain.addNode(d);
+
+        ChainEdge ab = new ChainEdge();
+        ab.setSource("a");
+        ab.setTarget("b");
+        chain.addEdge(ab);
+
+        ChainEdge ac = new ChainEdge();
+        ac.setSource("a");
+        ac.setTarget("c");
+        chain.addEdge(ac);
+
+
+        ChainEdge bd = new ChainEdge();
+        bd.setSource("b");
+        bd.setTarget("d");
+        chain.addEdge(bd);
+
+        ChainEdge cd = new ChainEdge();
+        cd.setSource("c");
+        cd.setTarget("d");
+        chain.addEdge(cd);
+
+        // A→B→D
+        //  ↘C↗
+        chain.executeForResult(new HashMap<>());
+
+        try {
+            Thread.sleep(3000);
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        }
+
+    }
+}