chore: improve tcp packets sent test by using tun interfaces

Author: Angelmmiguel

packages/tcpip/src/stack.test.ts

@@ -844,16 +844,28 @@ describe('tcp', () => {
   });
 
   test('tcp packets are sent immediately without delay', async () => {
-    const stack = await createStack();
+    const stack1 = await createStack();
+    const stack2 = await createStack();
 
-    const listener = await stack.listenTcp({
-      host: '127.0.0.1',
+    const tun1 = await stack1.createTunInterface({
+      ip: '192.168.1.1/24',
+    });
+
+    const tun2 = await stack2.createTunInterface({
+      ip: '192.168.1.2/24',
+    });
+
+    // Connect the two interfaces
+    tun1.readable.pipeTo(tun2.writable);
+    tun2.readable.pipeTo(tun1.writable);
+
+    const listener = await stack2.listenTcp({
       port: 8080,
     });
 
     const [outbound, inbound] = await Promise.all([
-      stack.connectTcp({
-        host: '127.0.0.1',
+      stack1.connectTcp({
+        host: '192.168.1.2',
         port: 8080,
       }),
       nextValue(listener),
@@ -866,20 +878,20 @@ describe('tcp', () => {
 
     // Record start time
     const startTime = performance.now();
-    
+
     // Write and read immediately
     await outboundWriter.write(data);
     const received = await inboundReader.read();
 
     // Record end time
     const endTime = performance.now();
-    
+
     expect(received.value).toStrictEqual(data);
-    
+
     // Check timing - with tcp_output enabled, this should be very fast
     // Without tcp_output, there would be a significant delay (~300ms)
     const elapsed = endTime - startTime;
-    expect(elapsed).toBeLessThan(200);
+    expect(elapsed).toBeCloseTo(0, -1);
   });
 });