From b158ae10ac113ef6f79eb81b7ce09ac730cda6ce Mon Sep 17 00:00:00 2001
From: LI123456mo <conellimo@gmail.com>
Date: Tue, 20 Jan 2026 20:14:41 +0300
Subject: [PATCH] test: add unit test for Utf8Utils

---
 .../dubbo/common/utils/Utf8UtilsTest.java     | 72 +++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 dubbo-common/src/test/java/org/apache/dubbo/common/utils/Utf8UtilsTest.java

diff --git a/dubbo-common/src/test/java/org/apache/dubbo/common/utils/Utf8UtilsTest.java b/dubbo-common/src/test/java/org/apache/dubbo/common/utils/Utf8UtilsTest.java
new file mode 100644
index 00000000000..cde1f0397eb
--- /dev/null
+++ b/dubbo-common/src/test/java/org/apache/dubbo/common/utils/Utf8UtilsTest.java
@@ -0,0 +1,72 @@
+/*
+ * 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.dubbo.common.utils;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class Utf8UtilsTest {
+
+    @Test
+    void shouldDecodeBasicAscii() {
+        // Just checking if it handles normal English letters (1 byte each)
+        byte[] bytes = "Dubbo".getBytes();
+        char[] dest = new char[bytes.length];
+
+        int resultLen = Utf8Utils.decodeUtf8(bytes, 0, bytes.length, dest, 0);
+
+        assertEquals(5, resultLen);
+        assertEquals("Dubbo", new String(dest));
+    }
+
+    @Test
+    void shouldHandleMultiByteCharacters() {
+        String input = "你好";
+        byte[] bytes = input.getBytes();
+        // Give it more space (6 instead of 2) to match the byte length
+        char[] dest = new char[bytes.length];
+
+        int resultLen = Utf8Utils.decodeUtf8(bytes, 0, bytes.length, dest, 0);
+
+        assertEquals(2, resultLen);
+        // We trim the string to only the parts that were actually filled
+        assertEquals("你好", new String(dest, 0, resultLen));
+    }
+
+    @Test
+    void shouldFailOnInvalidInput() {
+        // Poking the machine with a broken byte it shouldn't recognize
+        // 0xFE is not a valid UTF-8 start byte
+        byte[] badBytes = {(byte) 0xFE};
+        char[] dest = new char[1];
+
+        assertThrows(IllegalArgumentException.class, () -> {
+            Utf8Utils.decodeUtf8(badBytes, 0, 1, dest, 0);
+        });
+    }
+
+    @Test
+    void shouldHandleEmptyInput() {
+        // Making sure it doesn't freak out if we give it nothing
+        byte[] empty = new byte[0];
+        char[] dest = new char[0];
+
+        int result = Utf8Utils.decodeUtf8(empty, 0, 0, dest, 0);
+        assertEquals(0, result);
+    }
+}