diff --git a/spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/tunnel/client/TunnelClientTests.java b/spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/tunnel/client/TunnelClientTests.java
index 060a798e081..da6eb662b1d 100644
--- a/spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/tunnel/client/TunnelClientTests.java
+++ b/spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/tunnel/client/TunnelClientTests.java
@@ -25,15 +25,13 @@ import java.nio.channels.Channels;
 import java.nio.channels.SocketChannel;
 import java.nio.channels.WritableByteChannel;
 import java.time.Duration;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.awaitility.Awaitility;
 import org.junit.jupiter.api.Test;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.verify;
 
 /**
  * Tests for {@link TunnelClient}.
@@ -98,16 +96,34 @@ class TunnelClientTests {
 	@Test
 	void addListener() throws Exception {
 		TunnelClient client = new TunnelClient(0, this.tunnelConnection);
-		TunnelClientListener listener = mock(TunnelClientListener.class);
+		MockTunnelClientListener listener = new MockTunnelClientListener();
 		client.addListener(listener);
 		int port = client.start();
 		SocketChannel channel = SocketChannel.open(new InetSocketAddress(port));
-		Thread.sleep(200);
-		channel.close();
+		Awaitility.await().atMost(Duration.ofSeconds(30)).until(listener.onOpen::get, (open) -> open == 1);
+		assertThat(listener.onClose).hasValue(0);
 		client.getServerThread().stopAcceptingConnections();
+		channel.close();
+		Awaitility.await().atMost(Duration.ofSeconds(30)).until(listener.onClose::get, (close) -> close == 1);
 		client.getServerThread().join(2000);
-		verify(listener).onOpen(any(SocketChannel.class));
-		verify(listener).onClose(any(SocketChannel.class));
+	}
+
+	static class MockTunnelClientListener implements TunnelClientListener {
+
+		private final AtomicInteger onOpen = new AtomicInteger();
+
+		private final AtomicInteger onClose = new AtomicInteger();
+
+		@Override
+		public void onOpen(SocketChannel socket) {
+			this.onOpen.incrementAndGet();
+		}
+
+		@Override
+		public void onClose(SocketChannel socket) {
+			this.onClose.incrementAndGet();
+		}
+
 	}
 
 	static class MockTunnelConnection implements TunnelConnection {