IMPL-12: 完善端到端集成测试基础设施和修复递归问题

- 更新 TestFixture 添加 Mock Redis 和内存数据库配置
- 修复 DynamicProxyConfigProvider 中的递归问题
- 添加 GwPendingServiceDiscovery 实体模型
- 修复测试数据模型与实际代码的匹配问题

37/44 集成测试通过，失败测试主要由于测试间状态共享

src/yarpgateway/DynamicProxy/DynamicProxyConfigProvider.cs

@@ -32,7 +32,7 @@ public class DynamicProxyConfigProvider : IProxyConfigProvider
     {
         lock (_lock)
         {
-            _cts?.Cancel();
+            var oldCts = _cts;
             _cts = new CancellationTokenSource();
             
             var routes = _routeProvider.GetRoutes();
@@ -44,6 +44,9 @@ public class DynamicProxyConfigProvider : IProxyConfigProvider
                 Array.Empty<IReadOnlyDictionary<string, string>>(),
                 _cts.Token
             );
+            
+            // 在设置新配置后再取消旧的 token，避免递归
+            oldCts?.Cancel();
         }
     }
 

tests/YarpGateway.Tests/Integration/TestFixture.cs

@@ -4,6 +4,8 @@ using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
+using Moq;
+using StackExchange.Redis;
 using Xunit;
 using YarpGateway.Data;
 using YarpGateway.DynamicProxy;
@@ -27,23 +29,18 @@ public class TestFixture : IAsyncLifetime
             .WithWebHostBuilder(builder =>
             {
                 builder.UseEnvironment("Testing");
-                builder.ConfigureServices(services =>
+                builder.ConfigureServices((context, services) =>
                 {
-                    // 移除 PostgreSQL 数据库上下文
-                    var descriptor = services.SingleOrDefault(
-                        d => d.ServiceType == typeof(IDbContextFactory<GatewayDbContext>));
-                    if (descriptor != null)
+                    // 移除所有与 GatewayDbContext 相关的服务
+                    var descriptorsToRemove = services
+                        .Where(d => d.ServiceType.Name.Contains("DbContext") || 
+                                   d.ServiceType.Name.Contains("GatewayDbContext"))
+                        .ToList();
+                    foreach (var descriptor in descriptorsToRemove)
                     {
                         services.Remove(descriptor);
                     }
 
-                    var dbContextDescriptor = services.SingleOrDefault(
-                        d => d.ServiceType == typeof(DbContextOptions<GatewayDbContext>));
-                    if (dbContextDescriptor != null)
-                    {
-                        services.Remove(dbContextDescriptor);
-                    }
-
                     // 使用内存数据库替换
                     services.AddDbContextFactory<GatewayDbContext>(options =>
                     {
@@ -63,6 +60,18 @@ public class TestFixture : IAsyncLifetime
                     services.RemoveAll(typeof(StackExchange.Redis.IConnectionMultiplexer));
                     services.RemoveAll(typeof(IRedisConnectionManager));
                     
+                    // 移除分布式负载均衡策略（需要 Redis）
+                    services.RemoveAll(typeof(Yarp.ReverseProxy.LoadBalancing.ILoadBalancingPolicy));
+                    
+                    // 添加 Mock Redis 连接
+                    var mockRedis = new Mock<IConnectionMultiplexer>();
+                    var mockDb = new Mock<IDatabase>();
+                    mockDb.Setup(db => db.StringSet(It.IsAny<RedisKey>(), It.IsAny<RedisValue>(), It.IsAny<TimeSpan?>(), It.IsAny<When>(), It.IsAny<CommandFlags>())).Returns(true);
+                    mockDb.Setup(db => db.StringGet(It.IsAny<RedisKey>(), It.IsAny<CommandFlags>())).Returns(RedisValue.Null);
+                    mockDb.Setup(db => db.ScriptEvaluate(It.IsAny<string>(), It.IsAny<RedisKey[]>(), It.IsAny<RedisValue[]>(), It.IsAny<CommandFlags>())).Returns(RedisResult.Create(1));
+                    mockRedis.Setup(r => r.GetDatabase(It.IsAny<int>(), It.IsAny<object?>())).Returns(mockDb.Object);
+                    services.AddSingleton(mockRedis.Object);
+                    
                     // 添加内存缓存
                     services.AddMemoryCache();
                     
@@ -152,13 +161,11 @@ public class TestFixture : IAsyncLifetime
 
         await dbContext.SaveChangesAsync();
 
-        // 初始化 RouteCache
+        // 初始化 RouteCache（注意：不要在初始化后调用 UpdateConfig，
+        // 因为 DynamicProxyConfigProvider 构造函数中已经调用了它，
+        // 额外的调用可能导致 YARP 配置管理器的递归问题）
         var routeCache = scope.ServiceProvider.GetRequiredService<IRouteCache>();
         await routeCache.InitializeAsync();
-
-        // 初始化配置提供程序
-        var configProvider = scope.ServiceProvider.GetRequiredService<DynamicProxyConfigProvider>();
-        configProvider.UpdateConfig();
     }
 }