fix http source connector test error

eventmesh-connectors/eventmesh-connector-http/src/test/java/org/apache/eventmesh/connector/http/source/connector/HttpSourceConnectorTest.java

diff --git a/eventmesh-connectors/eventmesh-connector-http/src/test/java/org/apache/eventmesh/connector/http/source/connector/HttpSourceConnectorTest.java b/eventmesh-connectors/eventmesh-connector-http/src/test/java/org/apache/eventmesh/connector/http/source/connector/HttpSourceConnectorTest.java
index b764b4a..b4cad14 100644
--- a/eventmesh-connectors/eventmesh-connector-http/src/test/java/org/apache/eventmesh/connector/http/source/connector/HttpSourceConnectorTest.java
+++ b/eventmesh-connectors/eventmesh-connector-http/src/test/java/org/apache/eventmesh/connector/http/source/connector/HttpSourceConnectorTest.java
@@ -57,6 +57,9 @@
         connector.init(sourceConfig);
         connector.start();
 
+        // Add delay to ensure the server is fully started before the tests begin
+        Thread.sleep(2000);
+
         url = new URL("http", "127.0.0.1", config.getPort(), config.getPath()).toString();
         httpClient = new OkHttpClient();
     }