test: 添加系统设置和操作日志测试

单元测试:
- SystemSettingServiceTest: 测试服务类方法
- SystemSettingServiceCacheTest: 测试缓存功能

功能测试:
- SystemSettingsTest: 测试系统设置基础功能
- SystemSettingValidationTest: 测试表单验证规则
- ActivityLogTest: 测试操作日志功能

测试覆盖:
- 配置的读取和保存
- 配置验证规则
- 缓存机制
- 日志自动记录
- 日志筛选功能
- 日志详情查看

所有测试通过 ✓

tests/Feature/SystemSettingsTest.php

@@ -0,0 +1,122 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\SystemSetting;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class SystemSettingsTest extends TestCase
+{
+    use RefreshDatabase;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        
+        // 创建测试用户
+        $this->actingAs(User::factory()->create());
+    }
+
+    /** @test */
+    public function it_has_all_required_system_global_settings()
+    {
+        // 创建系统全局配置
+        $requiredSettings = [
+            'system.name' => ['name' => '知识库管理系统'],
+            'system.timeout' => ['timeout' => 60],
+            'system.max_retries' => ['max_retries' => 3],
+            'system.max_upload_size' => ['max_upload_size' => 10485760],
+            'system.allowed_file_types' => ['allowed_file_types' => ['pdf', 'docx', 'txt', 'md']],
+        ];
+
+        foreach ($requiredSettings as $key => $value) {
+            SystemSetting::create([
+                'key' => $key,
+                'value' => $value,
+                'group' => 'system',
+                'description' => '测试配置',
+            ]);
+        }
+
+        // 验证所有必需的系统全局配置都存在
+        $this->assertEquals(5, SystemSetting::where('group', 'system')->count());
+        
+        // 验证每个配置都能正确读取
+        $this->assertNotNull(SystemSetting::where('key', 'system.name')->first());
+        $this->assertNotNull(SystemSetting::where('key', 'system.timeout')->first());
+        $this->assertNotNull(SystemSetting::where('key', 'system.max_retries')->first());
+        $this->assertNotNull(SystemSetting::where('key', 'system.max_upload_size')->first());
+        $this->assertNotNull(SystemSetting::where('key', 'system.allowed_file_types')->first());
+    }
+
+    /** @test */
+    public function it_can_read_system_settings_values()
+    {
+        // 创建测试配置
+        SystemSetting::create([
+            'key' => 'system.name',
+            'value' => ['name' => '测试系统'],
+            'group' => 'system',
+            'description' => '系统名称',
+        ]);
+
+        SystemSetting::create([
+            'key' => 'system.timeout',
+            'value' => ['timeout' => 120],
+            'group' => 'system',
+            'description' => '超时时间',
+        ]);
+
+        // 验证能正确读取配置值
+        $nameSetting = SystemSetting::where('key', 'system.name')->first();
+        $this->assertEquals('测试系统', $nameSetting->value['name']);
+
+        $timeoutSetting = SystemSetting::where('key', 'system.timeout')->first();
+        $this->assertEquals(120, $timeoutSetting->value['timeout']);
+    }
+
+    /** @test */
+    public function it_validates_system_settings_structure()
+    {
+        // 验证系统全局配置的结构
+        $settings = [
+            'system.name' => 'string',
+            'system.timeout' => 'integer',
+            'system.max_retries' => 'integer',
+            'system.max_upload_size' => 'integer',
+            'system.allowed_file_types' => 'array',
+        ];
+
+        foreach ($settings as $key => $expectedType) {
+            $valueKey = explode('.', $key)[1];
+            
+            SystemSetting::create([
+                'key' => $key,
+                'value' => [$valueKey => $this->getTestValue($expectedType)],
+                'group' => 'system',
+                'description' => '测试',
+            ]);
+
+            $setting = SystemSetting::where('key', $key)->first();
+            $actualValue = $setting->value[$valueKey];
+            
+            $this->assertEquals(
+                $expectedType,
+                gettype($actualValue),
+                "配置 {$key} 的类型应该是 {$expectedType}"
+            );
+        }
+    }
+
+    private function getTestValue(string $type)
+    {
+        return match($type) {
+            'string' => '测试值',
+            'integer' => 100,
+            'array' => ['test'],
+            default => null,
+        };
+    }
+}