diff --git a/src/ZM/Utils/CatCode.php b/src/ZM/Utils/CatCode.php
index 15d6b6e8..8bb84227 100644
--- a/src/ZM/Utils/CatCode.php
+++ b/src/ZM/Utils/CatCode.php
@@ -11,7 +11,7 @@ class CatCode
     /**
      * 从 MessageSegment 转换为 CatCode 字符串
      */
-    public static function fromSegment(mixed $message_segment): string
+    public static function fromSegment(array|MessageSegment|string $message_segment): string
     {
         // 传入的必须是段数组或段对象
         if (is_array($message_segment)) {
@@ -24,13 +24,12 @@ class CatCode
             }
             return $str;
         }
+
         if ($message_segment instanceof MessageSegment) {
             return self::segment2CatCode($message_segment);
         }
-        if (is_string($message_segment)) {
-            return $message_segment;
-        }
-        return '';
+
+        return $message_segment;
     }
 
     /**
diff --git a/tests/ZM/Utils/CatCodeTest.php b/tests/ZM/Utils/CatCodeTest.php
new file mode 100644
index 00000000..8d09f810
--- /dev/null
+++ b/tests/ZM/Utils/CatCodeTest.php
@@ -0,0 +1,75 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\ZM\Utils;
+
+use OneBot\V12\Object\MessageSegment;
+use Tests\TestCase;
+use ZM\Utils\CatCode;
+
+/**
+ * @internal
+ */
+class CatCodeTest extends TestCase
+{
+    /**
+     * @dataProvider provideTestConvertFromSegment
+     */
+    public function testConvertFromSegment(mixed $segment, string $expected): void
+    {
+        $this->assertSame($expected, CatCode::fromSegment($segment));
+    }
+
+    public function provideTestConvertFromSegment(): array
+    {
+        return [
+            'string' => ['[CatCode:mention,user_id=123456789]', '[CatCode:mention,user_id=123456789]'],
+            'segment instance' => [new MessageSegment('mention', ['user_id' => '123456789']), '[CatCode:mention,user_id=123456789]'],
+            'multiple segment instance' => [
+                [
+                    new MessageSegment('mention', ['user_id' => '123456789']),
+                    new MessageSegment('text', ['text' => 'Hello']),
+                ],
+                '[CatCode:mention,user_id=123456789]Hello',
+            ],
+            'array contains non-segment' => [
+                [
+                    new MessageSegment('mention', ['user_id' => '123456789']),
+                    'Hello',
+                ],
+                '',
+            ],
+            'non-string, non-segment, non-array' => [123, ''],
+        ];
+    }
+
+    /**
+     * @dataProvider provideTestEscapeText
+     */
+    public function testEscapeText(string $text): void
+    {
+        $encoded = CatCode::encode($text);
+        $decoded = CatCode::decode($encoded);
+        $this->assertSame($text, $decoded);
+    }
+
+    public function provideTestEscapeText(): array
+    {
+        return [
+            ["前缀是'['后缀是']', 还有以及一个特殊的&"],
+            ["[前缀是'['后缀是']', 还有以及一个特殊的&"],
+            ["前缀是'['后缀是']', 还有以及一个特殊的"],
+            ["&前缀是'['后缀是']', 还有以及一个特殊的"],
+            ["&前缀是'['后缀是']', 还有以及一个特殊的]"],
+        ];
+    }
+
+    public function testEscapeTextForContent(): void
+    {
+        $text = "前缀是'['后缀是']', 还有以及一个特殊的&";
+        $encoded = CatCode::encode($text, true);
+        $decoded = CatCode::decode($encoded, true);
+        $this->assertSame($text, $decoded);
+    }
+}