Add exception unwrap method tests

components/data/data-services/org.wso2.micro.integrator.dataservices.core/src/test/java/org/wso2/micro/integrator/dataservices/core/test/DBUtilsTest.java

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+/*
+ * Copyright (c) 2025, WSO2 LLC. (https://www.wso2.com).
+ *
+ * WSO2 LLC. 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.wso2.micro.integrator.dataservices.core.test;
+
+import junit.framework.TestCase;
+import org.wso2.micro.integrator.dataservices.core.DBUtils;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.UndeclaredThrowableException;
+
+public class DBUtilsTest extends TestCase {
+
+    public void testUnwrapWithInvocationTargetException() {
+        Exception cause = new Exception("Root cause");
+        InvocationTargetException ite = new InvocationTargetException(cause);
+        Throwable result = DBUtils.unwrap(ite);
+        assertEquals(cause, result);
+    }
+
+    public void testUnwrapWithUndeclaredThrowableException() {
+        Exception cause = new Exception("Root cause");
+        UndeclaredThrowableException ute = new UndeclaredThrowableException(cause);
+        Throwable result = DBUtils.unwrap(ute);
+        assertEquals(cause, result);
+    }
+
+    public void testUnwrapWithNormalException() {
+        Exception ex = new Exception("Normal");
+        Throwable result = DBUtils.unwrap(ex);
+        assertEquals(ex, result);
+    }
+
+    public void testUnwrapWithNestedExceptions() {
+        Exception cause = new Exception("Root cause");
+        InvocationTargetException ite = new InvocationTargetException(cause);
+        UndeclaredThrowableException ute = new UndeclaredThrowableException(ite);
+        Throwable result = DBUtils.unwrap(ute);
+        assertEquals(cause, result);
+    }
+}