waf-platform/EdgeHttpDNS/sdk/ios/AlicloudHttpDNSTests/Network/HttpdnsNWHTTPClient_StateMachineTests.m

//
//  HttpdnsNWHTTPClient_StateMachineTests.m
//  TrustHttpDNSTests
//
//  @author Created by Claude Code on 2025-11-01
//  Copyright © 2025 trustapp.com. All rights reserved.
//
//  状æ€<C3A6>机测试 - 包å<E280A6>«çŠ¶æ€<C3A6>机与异常场æ™?(Q) 测试ç»?
//  测试总数�7 个（Q:17�
//

#import "HttpdnsNWHTTPClientTestBase.h"

@interface HttpdnsNWHTTPClient_StateMachineTests : HttpdnsNWHTTPClientTestBase

@end

@implementation HttpdnsNWHTTPClient_StateMachineTests

#pragma mark - Q. 状æ€<C3A6>机与异常场景测è¯?

// Q1.1 池溢出时LRU移除策略验è¯<C3A8>
- (void)testStateMachine_PoolOverflowLRU_RemovesOldestByLastUsedDate {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    // 需è¦<C3A8>并å<C2B6>‘创å»?个连接（串行请求会å¤<C3A5>用）
    NSMutableArray<XCTestExpectation *> *expectations = [NSMutableArray array];
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    // 并å<C2B6>‘å<E28098>‘èµ·5个请æ±?
    for (NSInteger i = 0; i < 5; i++) {
        XCTestExpectation *expectation = [self expectationWithDescription:[NSString stringWithFormat:@"Request %ld", (long)i]];
        [expectations addObject:expectation];

        dispatch_async(queue, ^{
            NSError *error = nil;
            // 使用 /delay/2 ç¡®ä¿<C3A4>所有请求å<E2809A>Œæ—¶åœ¨é£žè¡Œä¸­ï¼Œå¼ºåˆ¶åˆ›å»ºå¤šä¸ªè¿žæŽ¥
            [self.client performRequestWithURLString:@"http://127.0.0.1:11080/delay/2"
                                            userAgent:[NSString stringWithFormat:@"Request%ld", (long)i]
                                              timeout:15.0
                                                error:&error];
            [expectation fulfill];
        });
        [NSThread sleepForTimeInterval:0.05];  // å°<C3A5>é—´éš”é<E2809D>¿å…<C3A5>完全å<C2A8>Œæ—¶å<C2B6>¯åŠ?
    }

    [self waitForExpectations:expectations timeout:20.0];

    // 等待所有连接归�
    [NSThread sleepForTimeInterval:1.0];

    // 验è¯<C3A8>：池大å°<C3A5> â‰?4（LRU移除溢出部分ï¼?
    NSUInteger poolCount = [self.client connectionPoolCountForKey:poolKey];
    XCTAssertLessThanOrEqual(poolCount, 4,
                             @"Pool should enforce max 4 connections (LRU)");

    // 验è¯<C3A8>：创建了多个连接
    XCTAssertGreaterThanOrEqual(self.client.connectionCreationCount, 3,
                                @"Should create multiple concurrent connections");
}

// Q2.1 快速连续请求ä¸<C3A4>产生é‡<C3A9>å¤<C3A5>连接（间接验è¯<C3A8>å<EFBFBD>Œé‡<C3A9>归还防护）
- (void)testAbnormal_RapidSequentialRequests_NoDuplicates {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    // 快速连续å<C2AD>‘èµ?0个请求（测试连接归还的幂等性）
    for (NSInteger i = 0; i < 10; i++) {
        NSError *error = nil;
        HttpdnsNWHTTPClientResponse *response = [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                                                                userAgent:@"RapidTest"
                                                                                  timeout:15.0
                                                                                    error:&error];
        XCTAssertNotNil(response);
    }

    // 等待连接归还
    [NSThread sleepForTimeInterval:1.0];

    // 验è¯<C3A8>：池中最å¤?个连接（因为串行请求å¤<C3A5>用å<C2A8>Œä¸€è¿žæŽ¥ï¼?
    NSUInteger poolCount = [self.client connectionPoolCountForKey:poolKey];
    XCTAssertLessThanOrEqual(poolCount, 1,
                             @"Pool should have at most 1 connection (rapid sequential reuse)");

    // 验è¯<C3A8>：创建次数应该是1（所有请求å¤<C3A5>用å<C2A8>Œä¸€è¿žæŽ¥ï¼?
    XCTAssertEqual(self.client.connectionCreationCount, 1,
                   @"Should create only 1 connection for sequential requests");
}

// Q2.2 ä¸<C3A4>å<EFBFBD>Œç«¯å<C2AF>£è¯·æ±‚ä¸<C3A4>互相污染池
- (void)testAbnormal_DifferentPorts_IsolatedPools {
    [self.client resetPoolStatistics];
    NSString *poolKey11080 = @"127.0.0.1:11080:tcp";
    NSString *poolKey11443 = @"127.0.0.1:11443:tls";

    // å<>‘端å<C2AF>?1080å<30>‘起请求
    NSError *error1 = nil;
    HttpdnsNWHTTPClientResponse *response1 = [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                                                             userAgent:@"Port11080"
                                                                               timeout:15.0
                                                                                 error:&error1];
    XCTAssertNotNil(response1);

    // å<>‘端å<C2AF>?1443å<33>‘起请求
    NSError *error2 = nil;
    HttpdnsNWHTTPClientResponse *response2 = [self.client performRequestWithURLString:@"https://127.0.0.1:11443/get"
                                                                             userAgent:@"Port11443"
                                                                               timeout:15.0
                                                                                 error:&error2];
    XCTAssertNotNil(response2);

    // 等待连接归还
    [NSThread sleepForTimeInterval:0.5];

    // 验è¯<C3A8>：两个池å<C2A0>„自æœ?个连æŽ?
    XCTAssertEqual([self.client connectionPoolCountForKey:poolKey11080], 1,
                   @"Port 11080 pool should have 1 connection");
    XCTAssertEqual([self.client connectionPoolCountForKey:poolKey11443], 1,
                   @"Port 11443 pool should have 1 connection");

    // 验è¯<C3A8>：总共2个连接（池完全隔离）
    XCTAssertEqual([self.client totalConnectionCount], 2,
                   @"Total should be 2 (one per pool)");
}

// Q3.1 池大å°<C3A5>ä¸<C3A4>å<EFBFBD>˜å¼<C3A5>：任何时候池大å°<C3A5>都ä¸<C3A4>超过é™<C3A9>制
- (void)testInvariant_PoolSize_NeverExceedsLimit {
    [self.client resetPoolStatistics];

    // 快速连续å<C2AD>‘èµ?0个请求到å<C2B0>Œä¸€ç«¯ç‚¹
    for (NSInteger i = 0; i < 20; i++) {
        NSError *error = nil;
        [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                        userAgent:@"InvariantTest"
                                          timeout:15.0
                                            error:&error];
    }

    // 等待所有连接归�
    [NSThread sleepForTimeInterval:1.5];

    // 验è¯<C3A8>：æ¯<C3A6>个池的大å°<C3A5>ä¸<C3A4>超过4
    NSArray<NSString *> *allKeys = [self.client allConnectionPoolKeys];
    for (NSString *key in allKeys) {
        NSUInteger poolCount = [self.client connectionPoolCountForKey:key];
        XCTAssertLessThanOrEqual(poolCount, 4,
                                 @"Pool %@ size should never exceed 4 (actual: %lu)",
                                 key, (unsigned long)poolCount);
    }

    // 验è¯<C3A8>：总连接数也ä¸<C3A4>超过4（因为å<C2BA>ªæœ‰ä¸€ä¸ªæ± ï¼?
    XCTAssertLessThanOrEqual([self.client totalConnectionCount], 4,
                             @"Total connections should not exceed 4");
}

// Q3.3 æ— é‡<C3A9>å¤<C3A5>连接ä¸<C3A4>å<EFBFBD>˜å¼<C3A5>：并å<C2B6>‘请求ä¸<C3A4>产生é‡<C3A9>å¤<C3A5>
- (void)testInvariant_NoDuplicates_ConcurrentRequests {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    NSMutableArray<XCTestExpectation *> *expectations = [NSMutableArray array];
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    // 并å<C2B6>‘å<E28098>‘èµ·15个请求（å<CB86>¯èƒ½å¤<C3A5>用连接ï¼?
    for (NSInteger i = 0; i < 15; i++) {
        XCTestExpectation *expectation = [self expectationWithDescription:[NSString stringWithFormat:@"Request %ld", (long)i]];
        [expectations addObject:expectation];

        dispatch_async(queue, ^{
            NSError *error = nil;
            [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                            userAgent:@"ConcurrentTest"
                                              timeout:15.0
                                                error:&error];
            [expectation fulfill];
        });
    }

    [self waitForExpectations:expectations timeout:30.0];

    // 等待连接归还
    [NSThread sleepForTimeInterval:1.0];

    // 验è¯<C3A8>：池大å°<C3A5> â‰?4（ä¸<C3A4>å<EFBFBD>˜å¼<C3A5>ï¼?
    NSUInteger poolCount = [self.client connectionPoolCountForKey:poolKey];
    XCTAssertLessThanOrEqual(poolCount, 4,
                             @"Pool should not have duplicates (max 4 connections)");

    // 验è¯<C3A8>：创建的连接数å<C2B0>ˆç<CB86>†ï¼ˆâ‰?5，因为å<C2BA>¯èƒ½æœ‰å¤<C3A5>用ï¼?
    XCTAssertLessThanOrEqual(self.client.connectionCreationCount, 15,
                             @"Should not create excessive connections");
}

// Q4.1 边界æ<C592>¡ä»¶ï¼šæ<C5A1>°å¥?0秒å<E28099>Žè¿žæŽ¥è¿‡æœŸ
- (void)testBoundary_Exactly30Seconds_ConnectionExpired {
    if (getenv("SKIP_SLOW_TESTS")) {
        return;
    }

    [self.client resetPoolStatistics];

    // 第一个请�
    NSError *error1 = nil;
    HttpdnsNWHTTPClientResponse *response1 = [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                                                             userAgent:@"InitialRequest"
                                                                               timeout:15.0
                                                                                 error:&error1];
    XCTAssertNotNil(response1);

    // 等待æ<E280A6>°å¥½30.5秒（超过30秒过期时间）
    [NSThread sleepForTimeInterval:30.5];

    // 第二个请求：应该创建新连接（旧连接已过期�
    NSError *error2 = nil;
    HttpdnsNWHTTPClientResponse *response2 = [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                                                             userAgent:@"AfterExpiry"
                                                                               timeout:15.0
                                                                                 error:&error2];
    XCTAssertNotNil(response2);

    // 验è¯<C3A8>：创建了2个连接（旧连接过期，无法å¤<C3A5>用ï¼?
    XCTAssertEqual(self.client.connectionCreationCount, 2,
                   @"Should create 2 connections (first expired after 30s)");
    XCTAssertEqual(self.client.connectionReuseCount, 0,
                   @"Should not reuse expired connection");
}

// Q4.2 边界æ<C592>¡ä»¶ï¼?9秒内连接未过æœ?
- (void)testBoundary_Under30Seconds_ConnectionNotExpired {
    [self.client resetPoolStatistics];

    // 第一个请�
    NSError *error1 = nil;
    HttpdnsNWHTTPClientResponse *response1 = [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                                                             userAgent:@"InitialRequest"
                                                                               timeout:15.0
                                                                                 error:&error1];
    XCTAssertNotNil(response1);

    // 等待29秒（未到30秒过期时间）
    [NSThread sleepForTimeInterval:29.0];

    // 第二个请求：应该å¤<C3A5>用连接
    NSError *error2 = nil;
    HttpdnsNWHTTPClientResponse *response2 = [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                                                             userAgent:@"BeforeExpiry"
                                                                               timeout:15.0
                                                                                 error:&error2];
    XCTAssertNotNil(response2);

    // 验è¯<C3A8>：å<C5A1>ªåˆ›å»ºäº?个连接（å¤<C3A5>用了）
    XCTAssertEqual(self.client.connectionCreationCount, 1,
                   @"Should create only 1 connection (reused within 30s)");
    XCTAssertEqual(self.client.connectionReuseCount, 1,
                   @"Should reuse connection within 30s");
}

// Q4.3 边界æ<C592>¡ä»¶ï¼šæ<C5A1>°å¥?个连接全部ä¿<C3A4>ç•?
- (void)testBoundary_ExactlyFourConnections_AllKept {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    // 并å<C2B6>‘å<E28098>‘èµ·4个请求（使用延迟确ä¿<C3A4>å<EFBFBD>Œæ—¶åœ¨é£žè¡Œä¸­ï¼Œåˆ›å»?个独立连接）
    NSMutableArray<XCTestExpectation *> *expectations = [NSMutableArray array];
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    for (NSInteger i = 0; i < 4; i++) {
        XCTestExpectation *expectation = [self expectationWithDescription:
            [NSString stringWithFormat:@"Request %ld", (long)i]];
        [expectations addObject:expectation];

        dispatch_async(queue, ^{
            NSError *error = nil;
            // 使用 /delay/2 ç¡®ä¿<C3A4>所有请求å<E2809A>Œæ—¶åœ¨é£žè¡Œä¸?
            [self.client performRequestWithURLString:@"http://127.0.0.1:11080/delay/2"
                                            userAgent:[NSString stringWithFormat:@"Request%ld", (long)i]
                                              timeout:15.0
                                                error:&error];
            [expectation fulfill];
        });

        [NSThread sleepForTimeInterval:0.05];  // å°<C3A5>é—´éš”é<E2809D>¿å…<C3A5>完全å<C2A8>Œæ—¶å<C2B6>¯åŠ?
    }

    [self waitForExpectations:expectations timeout:20.0];

    // 等待连接归还
    [NSThread sleepForTimeInterval:1.0];

    // 验è¯<C3A8>：池æ<C2A0>°å¥½æœ?个连接（全部ä¿<C3A4>ç•™ï¼?
    NSUInteger poolCount = [self.client connectionPoolCountForKey:poolKey];
    XCTAssertEqual(poolCount, 4,
                   @"Pool should keep all 4 connections (not exceeding limit)");

    // 验è¯<C3A8>：æ<C5A1>°å¥½åˆ›å»?个连æŽ?
    XCTAssertEqual(self.client.connectionCreationCount, 4,
                   @"Should create exactly 4 connections");
}

// Q1.2 正常状æ€<C3A6>åº<C3A5>列验è¯?
- (void)testStateMachine_NormalSequence_StateTransitionsCorrect {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    // �步：创建并使用连�(CREATING �IN_USE �IDLE)
    HttpdnsNWHTTPClientResponse *response1 = [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                                                            userAgent:@"StateTest"
                                                                              timeout:15.0
                                                                                error:nil];
    XCTAssertNotNil(response1, @"First request should succeed");

    [NSThread sleepForTimeInterval:1.0];  // 等待归还

    // 验è¯<C3A8>：池中有1个连æŽ?
    XCTAssertEqual([self.client connectionPoolCountForKey:poolKey], 1,
                   @"Connection should be in pool");

    // ç¬?步：å¤<C3A5>用连接 (IDLE â†?IN_USE â†?IDLE)
    HttpdnsNWHTTPClientResponse *response2 = [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                                                            userAgent:@"StateTest"
                                                                              timeout:15.0
                                                                                error:nil];
    XCTAssertNotNil(response2, @"Second request should reuse connection");

    // 验è¯<C3A8>：å¤<C3A5>用计数增åŠ?
    XCTAssertEqual(self.client.connectionReuseCount, 1,
                   @"Should have reused connection once");
}

// Q1.3 inUse 标志维护验è¯<C3A8>
- (void)testStateMachine_InUseFlag_CorrectlyMaintained {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    // å<>‘起请求并归è¿?
    [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                    userAgent:@"InUseTest"
                                      timeout:15.0
                                        error:nil];

    [NSThread sleepForTimeInterval:1.0];  // 等待归还

    // 获å<C2B7>–池中连接
    NSArray<HttpdnsNWReusableConnection *> *connections = [self.client connectionsInPoolForKey:poolKey];
    XCTAssertEqual(connections.count, 1, @"Should have 1 connection in pool");

    // 验è¯<C3A8>：池中连接的 inUse 应为 NO
    for (HttpdnsNWReusableConnection *conn in connections) {
        XCTAssertFalse(conn.inUse, @"Connection in pool should not be marked as inUse");
    }
}

// Q2.3 Nil lastUsedDate 处ç<E2809E>†éªŒè¯<C3A8>
- (void)testAbnormal_NilLastUsedDate_HandledGracefully {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    // å<>‘起请求创建连接
    [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                    userAgent:@"NilDateTest"
                                      timeout:15.0
                                        error:nil];

    [NSThread sleepForTimeInterval:1.0];

    // 获å<C2B7>–连接并设ç½?lastUsedDate ä¸?nil
    NSArray<HttpdnsNWReusableConnection *> *connections = [self.client connectionsInPoolForKey:poolKey];
    XCTAssertEqual(connections.count, 1, @"Should have connection");

    HttpdnsNWReusableConnection *conn = connections.firstObject;
    [conn debugSetLastUsedDate:nil];

    // å<>‘起新请求触å<C2A6>?prune（内部应使用 distantPast 处ç<E2809E>† nilï¼?
    HttpdnsNWHTTPClientResponse *response = [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                                                            userAgent:@"NilDateTest"
                                                                              timeout:15.0
                                                                                error:nil];

    // 验è¯<C3A8>：ä¸<C3A4>崩溃，正常工ä½?
    XCTAssertNotNil(response, @"Should handle nil lastUsedDate gracefully");
}

// Q3.2 池中无失效连接ä¸<C3A4>å<EFBFBD>˜å¼<C3A5>
- (void)testInvariant_NoInvalidatedInPool {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    // å<>‘起多个请求（包括æˆ<C3A6>功和超时ï¼?
    for (NSInteger i = 0; i < 3; i++) {
        [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                        userAgent:@"InvariantTest"
                                          timeout:15.0
                                            error:nil];
    }

    // å<>‘èµ·1个超时请æ±?
    [self.client performRequestWithURLString:@"http://127.0.0.1:11080/delay/10"
                                    userAgent:@"TimeoutTest"
                                      timeout:0.5
                                        error:nil];

    [NSThread sleepForTimeInterval:2.0];

    // 获å<C2B7>–池中所有连æŽ?
    NSArray<HttpdnsNWReusableConnection *> *connections = [self.client connectionsInPoolForKey:poolKey];

    // 验è¯<C3A8>：池中无失效连接
    for (HttpdnsNWReusableConnection *conn in connections) {
        XCTAssertFalse(conn.isInvalidated, @"Pool should not contain invalidated connections");
    }
}

// Q3.4 lastUsedDate å<>•è°ƒæ€§éªŒè¯?
- (void)testInvariant_LastUsedDate_Monotonic {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    // �次使�
    [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                    userAgent:@"MonotonicTest"
                                      timeout:15.0
                                        error:nil];

    [NSThread sleepForTimeInterval:1.0];

    NSArray<HttpdnsNWReusableConnection *> *connections1 = [self.client connectionsInPoolForKey:poolKey];
    XCTAssertEqual(connections1.count, 1, @"Should have connection");
    NSDate *date1 = connections1.firstObject.lastUsedDate;
    XCTAssertNotNil(date1, @"lastUsedDate should be set");

    // 等待1秒确ä¿<C3A4>时间推è¿?
    [NSThread sleepForTimeInterval:1.0];

    // ç¬?次使用å<C2A8>Œä¸€è¿žæŽ¥
    [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                    userAgent:@"MonotonicTest"
                                      timeout:15.0
                                        error:nil];

    [NSThread sleepForTimeInterval:1.0];

    NSArray<HttpdnsNWReusableConnection *> *connections2 = [self.client connectionsInPoolForKey:poolKey];
    XCTAssertEqual(connections2.count, 1, @"Should still have 1 connection");
    NSDate *date2 = connections2.firstObject.lastUsedDate;

    // 验è¯<C3A8>：lastUsedDate 递增
    XCTAssertTrue([date2 timeIntervalSinceDate:date1] > 0,
                  @"lastUsedDate should increase after reuse");
}

// Q5.1 超时+池溢出å¤<C3A5>å<EFBFBD>ˆåœºæ™?
- (void)testCompound_TimeoutDuringPoolOverflow_Handled {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    // 先填满池ï¼?个æˆ<C3A6>功连接）
    NSMutableArray<XCTestExpectation *> *expectations = [NSMutableArray array];
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    for (NSInteger i = 0; i < 4; i++) {
        XCTestExpectation *expectation = [self expectationWithDescription:
            [NSString stringWithFormat:@"Fill pool %ld", (long)i]];
        [expectations addObject:expectation];

        dispatch_async(queue, ^{
            [self.client performRequestWithURLString:@"http://127.0.0.1:11080/delay/2"
                                            userAgent:@"CompoundTest"
                                              timeout:15.0
                                                error:nil];
            [expectation fulfill];
        });
        [NSThread sleepForTimeInterval:0.05];
    }

    [self waitForExpectations:expectations timeout:20.0];
    [NSThread sleepForTimeInterval:1.0];

    NSUInteger poolCountBefore = [self.client connectionPoolCountForKey:poolKey];
    XCTAssertLessThanOrEqual(poolCountBefore, 4, @"Pool should have � connections");

    // �个请求超�
    NSError *error = nil;
    HttpdnsNWHTTPClientResponse *response = [self.client performRequestWithURLString:@"http://127.0.0.1:11080/delay/10"
                                                                            userAgent:@"TimeoutRequest"
                                                                              timeout:0.5
                                                                                error:&error];

    XCTAssertNil(response, @"Timeout request should return nil");
    XCTAssertNotNil(error, @"Should have error");

    [NSThread sleepForTimeInterval:1.0];

    // 验è¯<C3A8>：超时连接未加入æ±?
    NSUInteger poolCountAfter = [self.client connectionPoolCountForKey:poolKey];
    XCTAssertLessThanOrEqual(poolCountAfter, 4, @"Timed-out connection should not be added to pool");
}

// Q2.4 打开失败ä¸<C3A4>加入池
- (void)testAbnormal_OpenFailure_NotAddedToPool {
    [self.client resetPoolStatistics];

    // å°<C3A5>试连接无效端å<C2AF>£ï¼ˆè¿žæŽ¥æ‹’ç»<C3A7>）
    NSError *error = nil;
    HttpdnsNWHTTPClientResponse *response = [self.client performRequestWithURLString:@"http://127.0.0.1:99999/get"
                                                                            userAgent:@"FailureTest"
                                                                              timeout:2.0
                                                                                error:&error];

    // 验è¯<C3A8>：请求失è´?
    XCTAssertNil(response, @"Should fail to connect to invalid port");

    // 验è¯<C3A8>：无连接加入æ±?
    XCTAssertEqual([self.client totalConnectionCount], 0,
                   @"Failed connection should not be added to pool");
}

// Q2.5 多次 invalidate 幂等�
- (void)testAbnormal_MultipleInvalidate_Idempotent {
    [self.client resetPoolStatistics];
    NSString *poolKey = @"127.0.0.1:11080:tcp";

    // 创建连接
    [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                    userAgent:@"InvalidateTest"
                                      timeout:15.0
                                        error:nil];

    [NSThread sleepForTimeInterval:1.0];

    NSArray<HttpdnsNWReusableConnection *> *connections = [self.client connectionsInPoolForKey:poolKey];
    XCTAssertEqual(connections.count, 1, @"Should have connection");

    HttpdnsNWReusableConnection *conn = connections.firstObject;

    // 多次 invalidate
    [conn debugInvalidate];
    [conn debugInvalidate];
    [conn debugInvalidate];

    // 验è¯<C3A8>：ä¸<C3A4>崩溃
    XCTAssertTrue(conn.isInvalidated, @"Connection should be invalidated");
}

// Q5.2 并å<C2B6>‘ dequeue ç«žæ€<C3A6>测è¯?
- (void)testCompound_ConcurrentDequeueDuringPrune_Safe {
    [self.client resetPoolStatistics];

    // 在两个端å<C2AF>£åˆ›å»ºè¿žæŽ?
    [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                    userAgent:@"RaceTest"
                                      timeout:15.0
                                        error:nil];

    [self.client performRequestWithURLString:@"http://127.0.0.1:11443/get"
                                    userAgent:@"RaceTest"
                                      timeout:15.0
                                        error:nil];

    [NSThread sleepForTimeInterval:1.0];

    // 等待30秒让连接过期
    [NSThread sleepForTimeInterval:30.5];

    // 并å<C2B6>‘触å<C2A6>‘两个端å<C2AF>£çš?dequeue（会触å<C2A6>‘ pruneï¼?
    dispatch_group_t group = dispatch_group_create();
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_group_async(group, queue, ^{
        [self.client performRequestWithURLString:@"http://127.0.0.1:11080/get"
                                        userAgent:@"Race1"
                                          timeout:15.0
                                            error:nil];
    });

    dispatch_group_async(group, queue, ^{
        [self.client performRequestWithURLString:@"http://127.0.0.1:11443/get"
                                        userAgent:@"Race2"
                                          timeout:15.0
                                            error:nil];
    });

    // 等待完æˆ<C3A6>
    dispatch_group_wait(group, dispatch_time(DISPATCH_TIME_NOW, 20 * NSEC_PER_SEC));

    // 验è¯<C3A8>：无崩溃，连接池正常工作
    NSUInteger totalCount = [self.client totalConnectionCount];
    XCTAssertLessThanOrEqual(totalCount, 4, @"Pool should remain stable after concurrent prune");
}

@end