[ISSUE #4547] Add unit test for OpenFunctionSourceConnector. (#4561)

* Added test for OpenFunction Source Connector

* Removed Redundant @SPY annnotation

* WIP resolved checkstyle errors

eventmesh-connectors/eventmesh-connector-openfunction/src/test/java/org/apache/eventmesh/connector/openfunction/source/connector/OpenFunctionSourceConnectorTest.java

@@ -0,0 +1,63 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.eventmesh.connector.openfunction.source.connector;
+
+import org.apache.eventmesh.connector.openfunction.source.config.OpenFunctionSourceConfig;
+import org.apache.eventmesh.openconnect.offsetmgmt.api.data.ConnectRecord;
+import org.apache.eventmesh.openconnect.offsetmgmt.api.data.RecordOffset;
+import org.apache.eventmesh.openconnect.offsetmgmt.api.data.RecordPartition;
+
+import java.util.List;
+import java.util.concurrent.BlockingQueue;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class OpenFunctionSourceConnectorTest {
+
+    private final OpenFunctionSourceConnector connector = new OpenFunctionSourceConnector();
+
+    @Test
+    public void testSpringSourceConnector() throws Exception {
+        OpenFunctionSourceConfig sourceConfig = new OpenFunctionSourceConfig();
+        connector.init(sourceConfig);
+        connector.start();
+        final int count = 5;
+        final String message = "testMessage";
+        writeMockedRecords(count, message);
+        List<ConnectRecord> connectRecords = connector.poll();
+        Assertions.assertEquals(count, connectRecords.size());
+        for (int i = 0; i < connectRecords.size(); i++) {
+            Object actualMessage = String.valueOf(connectRecords.get(i).getData());
+            String expectedMessage = "testMessage" + i;
+            Assertions.assertEquals(expectedMessage, actualMessage);
+        }
+        connector.stop();
+    }
+
+    private void writeMockedRecords(int count, String message) {
+        BlockingQueue<ConnectRecord> queue = connector.queue();
+        for (int i = 0; i < count; i++) {
+            RecordPartition partition = new RecordPartition();
+            RecordOffset offset = new RecordOffset();
+            ConnectRecord record = new ConnectRecord(partition, offset, System.currentTimeMillis(), message + i);
+            queue.offer(record);
+        }
+    }
+
+}