Add server to test.

Author: sarahchen6

utils/socket-utils/build.gradle

@@ -9,6 +9,10 @@ sourceSets {
   main_java17 {
     java.srcDirs "${project.projectDir}/src/main/java17"
   }
+
+  test_java17 {
+    java.srcDirs "${project.projectDir}/src/test/java17"
+  }
 }
 
 compileMain_java17Java.configure {

utils/socket-utils/src/test/java17/datadog/common/socket/TunnelingJdkSocketTest.java

@@ -3,31 +3,60 @@
 import static org.junit.jupiter.api.Assertions.assertTimeoutPreemptively;
 
 import java.io.IOException;
+import java.nio.channels.ServerSocketChannel;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.time.Duration;
+import java.util.concurrent.atomic.AtomicBoolean;
+import jnr.unixsocket.UnixSocketAddress;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 public class TunnelingJdkSocketTest {
 
+  private final AtomicBoolean running = new AtomicBoolean(false);
+
   @Test
   public void testTimeout() throws Exception {
     Assertions.assertEquals(1 + 1, 3); // should fail
 
     // create test path
     Path socketPath = Files.createTempFile("testSocket", null);
+    // start server
+    startServer(socketPath);
     // create client socket
     TunnelingJdkSocket clientSocket = createClient(socketPath);
 
     // attempt to read from empty socket (read should block indefinitely)
     assertTimeoutPreemptively(Duration.ofSeconds(5), () -> clientSocket.getInputStream().read());
 
-    // clean up
+    // clean up client, server, and path
     clientSocket.close();
+    running.set(false);
     Files.deleteIfExists(socketPath);
   }
 
+  private void startServer(Path socketPath) {
+    Thread serverThread =
+        new Thread(
+            () -> {
+              // open and bind server to socketPath
+              try (ServerSocketChannel serverChannel = ServerSocketChannel.open()) {
+                serverChannel.socket().bind(new UnixSocketAddress(socketPath.toFile()));
+                // accept connections made to the server
+                running.set(true);
+                while (running.get()) {
+                  serverChannel.accept();
+                }
+              } catch (IOException e) {
+                throw new RuntimeException(e);
+              }
+            });
+
+    // start server in separate thread
+    serverThread.start();
+  }
+
   private TunnelingJdkSocket createClient(Path socketPath) throws IOException {
     // create client socket
     TunnelingJdkSocket clientSocket = new TunnelingJdkSocket(socketPath);