diff --git a/pom.xml b/pom.xml
index 7d13c6f..b5e6963 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 	<artifactId>fess-webapp-example</artifactId>
 	<packaging>jar</packaging>
 	<name>Example Webapp Plugin</name>
-	<version>15.4.0-SNAPSHOT</version>
+	<version>15.5.0-SNAPSHOT</version>
 	<scm>
 		<connection>scm:git:git@github.com:codelibs/fess-webapp-example.git</connection>
 		<developerConnection>scm:git:git@github.com:codelibs/fess-webapp-example.git</developerConnection>
@@ -15,7 +15,7 @@
 	<parent>
 		<groupId>org.codelibs.fess</groupId>
 		<artifactId>fess-parent</artifactId>
-		<version>15.4.0</version>
+		<version>15.5.0-SNAPSHOT</version>
 		<relativePath />
 	</parent>
 	<build>
diff --git a/src/test/java/org/codelibs/fess/plugin/webapp/helper/CustomSystemHelperTest.java b/src/test/java/org/codelibs/fess/plugin/webapp/helper/CustomSystemHelperTest.java
index 89e3f37..4eec237 100644
--- a/src/test/java/org/codelibs/fess/plugin/webapp/helper/CustomSystemHelperTest.java
+++ b/src/test/java/org/codelibs/fess/plugin/webapp/helper/CustomSystemHelperTest.java
@@ -15,6 +15,8 @@
  */
 package org.codelibs.fess.plugin.webapp.helper;
 
+import org.junit.jupiter.api.TestInfo;
+
 import java.nio.file.Path;
 import java.nio.file.Paths;
 
@@ -25,9 +27,9 @@
 import org.apache.logging.log4j.core.config.LoggerConfig;
 import org.codelibs.fess.mylasta.direction.FessConfig;
 import org.codelibs.fess.util.ComponentUtil;
-import org.dbflute.utflute.lastaflute.LastaFluteTestCase;
+import org.codelibs.fess.webapp.example.UnitWebappTestCase;
 
-public class CustomSystemHelperTest extends LastaFluteTestCase {
+public class CustomSystemHelperTest extends UnitWebappTestCase {
 
     @Override
     protected String prepareConfigFile() {
@@ -40,7 +42,7 @@ protected boolean isSuppressTestCaseTransaction() {
     }
 
     @Override
-    public void setUp() throws Exception {
+    public void setUp(TestInfo testInfo) throws Exception {
         ComponentUtil.setFessConfig(new FessConfig.SimpleImpl() {
             private static final long serialVersionUID = 1L;
 
@@ -60,13 +62,13 @@ public String[] getSupportedLanguagesAsArray() {
             }
 
         });
-        super.setUp();
+        super.setUp(testInfo);
     }
 
     @Override
-    public void tearDown() throws Exception {
+    public void tearDown(TestInfo testInfo) throws Exception {
         ComponentUtil.setFessConfig(null);
-        super.tearDown();
+        super.tearDown(testInfo);
     }
 
     public void test_checkProperty() {
@@ -314,14 +316,8 @@ public void test_parseProjectProperties_consistencyAcrossInstances() {
     public void test_parseProjectProperties_withDifferentPathTypes() {
         // Given
         CustomSystemHelper helper = new CustomSystemHelper();
-        Path[] testPaths = {
-                null,
-                Paths.get(""),
-                Paths.get("relative/path"),
-                Paths.get("/absolute/path"),
-                Paths.get("../parent/path"),
-                Paths.get("./current/path")
-        };
+        Path[] testPaths = { null, Paths.get(""), Paths.get("relative/path"), Paths.get("/absolute/path"), Paths.get("../parent/path"),
+                Paths.get("./current/path") };
 
         // When & Then
         for (Path testPath : testPaths) {
@@ -374,14 +370,8 @@ public void test_parseProjectProperties_idempotency() {
     public void test_parseProjectProperties_doesNotThrowException() {
         // Given
         CustomSystemHelper helper = new CustomSystemHelper();
-        Path[] problematicPaths = {
-                null,
-                Paths.get(""),
-                Paths.get("/"),
-                Paths.get("non/existent/path"),
-                Paths.get("\\invalid\\path"),
-                Paths.get("special!@#$%/path")
-        };
+        Path[] problematicPaths = { null, Paths.get(""), Paths.get("/"), Paths.get("non/existent/path"), Paths.get("\\invalid\\path"),
+                Paths.get("special!@#$%/path") };
 
         // When & Then
         for (Path testPath : problematicPaths) {
diff --git a/src/test/java/org/codelibs/fess/webapp/example/UnitWebappTestCase.java b/src/test/java/org/codelibs/fess/webapp/example/UnitWebappTestCase.java
new file mode 100644
index 0000000..58cb0f4
--- /dev/null
+++ b/src/test/java/org/codelibs/fess/webapp/example/UnitWebappTestCase.java
@@ -0,0 +1,109 @@
+/*
+ * Copyright 2012-2025 CodeLibs Project and the Others.
+ *
+ * Licensed 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.codelibs.fess.webapp.example;
+
+import org.codelibs.fess.util.ComponentUtil;
+import org.dbflute.utflute.lastaflute.LastaFluteTestCase;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.TestInfo;
+
+public abstract class UnitWebappTestCase extends LastaFluteTestCase {
+    private static final ThreadLocal<TestInfo> currentTestInfo = new ThreadLocal<>();
+
+    @Override
+    protected String prepareConfigFile() {
+        return "test_app.xml";
+    }
+
+    @Override
+    protected void setUp(TestInfo testInfo) throws Exception {
+        currentTestInfo.set(testInfo);
+        super.setUp(testInfo);
+    }
+
+    @Override
+    protected void tearDown(TestInfo testInfo) throws Exception {
+        ComponentUtil.setFessConfig(null);
+        super.tearDown(testInfo);
+    }
+
+    protected String getName() {
+        TestInfo info = currentTestInfo.get();
+        return info != null ? info.getDisplayName() : "unknown";
+    }
+
+    // ===== Assert methods for JUnit 4/5 compatibility =====
+
+    protected void fail(String message) {
+        Assertions.fail(message);
+    }
+
+    protected void assertTrue(String message, boolean condition) {
+        Assertions.assertTrue(condition, message);
+    }
+
+    protected void assertFalse(String message, boolean condition) {
+        Assertions.assertFalse(condition, message);
+    }
+
+    protected void assertEquals(String message, Object expected, Object actual) {
+        Assertions.assertEquals(expected, actual, message);
+    }
+
+    protected void assertEquals(String message, long expected, long actual) {
+        Assertions.assertEquals(expected, actual, message);
+    }
+
+    protected void assertEquals(String message, double expected, double actual, double delta) {
+        Assertions.assertEquals(expected, actual, delta, message);
+    }
+
+    protected void assertEquals(double expected, double actual, double delta) {
+        Assertions.assertEquals(expected, actual, delta);
+    }
+
+    protected void assertEquals(String message, float expected, float actual, float delta) {
+        Assertions.assertEquals(expected, actual, delta, message);
+    }
+
+    protected void assertEquals(float expected, float actual, float delta) {
+        Assertions.assertEquals(expected, actual, delta);
+    }
+
+    protected void assertNotNull(String message, Object object) {
+        Assertions.assertNotNull(object, message);
+    }
+
+    protected void assertNull(String message, Object object) {
+        Assertions.assertNull(object, message);
+    }
+
+    protected void assertSame(Object expected, Object actual) {
+        Assertions.assertSame(expected, actual);
+    }
+
+    protected void assertSame(String message, Object expected, Object actual) {
+        Assertions.assertSame(expected, actual, message);
+    }
+
+    protected void assertNotSame(Object expected, Object actual) {
+        Assertions.assertNotSame(expected, actual);
+    }
+
+    protected void assertNotSame(String message, Object expected, Object actual) {
+        Assertions.assertNotSame(expected, actual, message);
+    }
+}