[codex] Extract BLE service policy helpers (#1321)

* Extract BLE service policy helpers * Stabilize image media transfer test --------- Co-authored-by: jack <jackjackbits@users.noreply.github.com>
2026-07-25 02:25:20 +00:00 · 2026-06-01 14:16:44 +02:00
parent ffa0d7aa4f
commit 193cfdc06a
16 changed files with 1565 additions and 486 deletions
@@ -0,0 +1,148 @@
+import BitFoundation
+import Foundation
+import Testing
+@testable import bitchat
+
+@Suite("BLE ingress packet guard tests")
+struct BLEIngressPacketGuardTests {
+    @Test("valid packets return the received and validation peer context")
+    func validPacketsReturnContext() throws {
+        let local = PeerID(str: "0011223344556677")
+        let bound = PeerID(str: "1122334455667788")
+        let sender = PeerID(str: "8899aabbccddeeff")
+        let packet = makePacket(sender: sender, timestamp: 1_000)
+
+        let context = try #require(success(BLEIngressPacketGuard.evaluate(
+            packet: packet,
+            claimedSenderID: sender,
+            boundPeerID: bound,
+            localPeerID: local,
+            directAnnounceTTL: 7,
+            nowMs: 1_000,
+            isValidSyncResponse: { _ in false }
+        )))
+
+        #expect(context.receivedFromPeerID == bound)
+        #expect(context.validationPeerID == sender)
+    }
+
+    @Test("self loopback and direct announce spoofing are rejected before timestamp checks")
+    func linkBindingRejectionsWinBeforeTimestampChecks() {
+        let local = PeerID(str: "0011223344556677")
+        let bound = PeerID(str: "1122334455667788")
+        let claimed = PeerID(str: "8899aabbccddeeff")
+        let selfPacket = makePacket(sender: local, timestamp: 0)
+        let spoofedAnnounce = makePacket(type: .announce, sender: claimed, timestamp: 0, ttl: 7)
+
+        let selfResult = BLEIngressPacketGuard.evaluate(
+            packet: selfPacket,
+            claimedSenderID: local,
+            boundPeerID: bound,
+            localPeerID: local,
+            directAnnounceTTL: 7,
+            nowMs: 1_000_000,
+            isValidSyncResponse: { _ in false }
+        )
+        let spoofResult = BLEIngressPacketGuard.evaluate(
+            packet: spoofedAnnounce,
+            claimedSenderID: claimed,
+            boundPeerID: bound,
+            localPeerID: local,
+            directAnnounceTTL: 7,
+            nowMs: 1_000_000,
+            isValidSyncResponse: { _ in false }
+        )
+
+        #expect(selfResult == .failure(.selfLoopback(packetType: MessageType.message.rawValue)))
+        #expect(spoofResult == .failure(.directSenderMismatch(boundPeerID: bound, claimedSenderID: claimed)))
+    }
+
+    @Test("timestamp skew outside the window is rejected")
+    func timestampSkewIsRejected() {
+        let local = PeerID(str: "0011223344556677")
+        let sender = PeerID(str: "1122334455667788")
+        let packet = makePacket(sender: sender, timestamp: 1_000)
+
+        let result = BLEIngressPacketGuard.evaluate(
+            packet: packet,
+            claimedSenderID: sender,
+            boundPeerID: nil,
+            localPeerID: local,
+            directAnnounceTTL: 7,
+            nowMs: 200_000,
+            maxTimestampSkewMs: 120_000,
+            isValidSyncResponse: { _ in false }
+        )
+
+        #expect(result == .failure(.timestampSkew(
+            peerID: sender,
+            skewMs: 199_000,
+            maxSkewMs: 120_000
+        )))
+    }
+
+    @Test("valid RSR packets use bound peer validation and bypass timestamp skew")
+    func validRSRUsesBoundPeerAndBypassesTimestamp() throws {
+        let local = PeerID(str: "0011223344556677")
+        let bound = PeerID(str: "1122334455667788")
+        let sender = PeerID(str: "8899aabbccddeeff")
+        var packet = makePacket(sender: sender, timestamp: 1)
+        packet.isRSR = true
+
+        let context = try #require(success(BLEIngressPacketGuard.evaluate(
+            packet: packet,
+            claimedSenderID: sender,
+            boundPeerID: bound,
+            localPeerID: local,
+            directAnnounceTTL: 7,
+            nowMs: 1_000_000,
+            isValidSyncResponse: { $0 == bound }
+        )))
+
+        #expect(context.receivedFromPeerID == bound)
+        #expect(context.validationPeerID == bound)
+    }
+
+    @Test("invalid RSR packets are rejected")
+    func invalidRSRIsRejected() {
+        let local = PeerID(str: "0011223344556677")
+        let bound = PeerID(str: "1122334455667788")
+        let sender = PeerID(str: "8899aabbccddeeff")
+        var packet = makePacket(sender: sender, timestamp: 1)
+        packet.isRSR = true
+
+        let result = BLEIngressPacketGuard.evaluate(
+            packet: packet,
+            claimedSenderID: sender,
+            boundPeerID: bound,
+            localPeerID: local,
+            directAnnounceTTL: 7,
+            nowMs: 1_000_000,
+            isValidSyncResponse: { _ in false }
+        )
+
+        #expect(result == .failure(.invalidRSR(peerID: bound)))
+    }
+
+    private func makePacket(
+        type: MessageType = .message,
+        sender: PeerID,
+        timestamp: UInt64,
+        ttl: UInt8 = 3
+    ) -> BitchatPacket {
+        BitchatPacket(
+            type: type.rawValue,
+            senderID: Data(hexString: sender.id) ?? Data(),
+            recipientID: nil,
+            timestamp: timestamp,
+            payload: Data([0x01, 0x02, 0x03]),
+            signature: nil,
+            ttl: ttl
+        )
+    }
+
+    private func success(_ result: Result<BLEIngressPacketContext, BLEIngressPacketGuard.Rejection>) -> BLEIngressPacketContext? {
+        guard case .success(let context) = result else { return nil }
+        return context
+    }
+}
@@ -0,0 +1,36 @@
+import Foundation
+import Testing
+@testable import bitchat
+
+@Suite("BLE log rate limiter tests")
+struct BLELogRateLimiterTests {
+    @Test("repeated log keys are suppressed until the default interval elapses")
+    func suppressesRepeatedKeysUntilIntervalElapses() {
+        let limiter = BLELogRateLimiter(defaultMinimumInterval: 5)
+        let now = Date(timeIntervalSince1970: 100)
+
+        #expect(limiter.shouldLog(key: "ready:peer-a", now: now))
+        #expect(!limiter.shouldLog(key: "ready:peer-a", now: now.addingTimeInterval(4.9)))
+        #expect(limiter.shouldLog(key: "ready:peer-a", now: now.addingTimeInterval(5)))
+    }
+
+    @Test("different log keys are tracked independently")
+    func tracksKeysIndependently() {
+        let limiter = BLELogRateLimiter(defaultMinimumInterval: 5)
+        let now = Date(timeIntervalSince1970: 100)
+
+        #expect(limiter.shouldLog(key: "ready:peer-a", now: now))
+        #expect(limiter.shouldLog(key: "ready:peer-b", now: now))
+        #expect(!limiter.shouldLog(key: "ready:peer-a", now: now.addingTimeInterval(1)))
+    }
+
+    @Test("call sites can override the default interval")
+    func supportsPerCallIntervals() {
+        let limiter = BLELogRateLimiter(defaultMinimumInterval: 5)
+        let now = Date(timeIntervalSince1970: 100)
+
+        #expect(limiter.shouldLog(key: "self-loopback", now: now, minimumInterval: 30))
+        #expect(!limiter.shouldLog(key: "self-loopback", now: now.addingTimeInterval(29), minimumInterval: 30))
+        #expect(limiter.shouldLog(key: "self-loopback", now: now.addingTimeInterval(30), minimumInterval: 30))
+    }
+}
@@ -0,0 +1,136 @@
+import BitFoundation
+import Foundation
+import Testing
+@testable import bitchat
+
+@Suite("BLE outbound fragment planner tests")
+struct BLEOutboundFragmentPlannerTests {
+    @Test("planner splits packets and preserves reassembled payload")
+    func plannerSplitsAndReassemblesPacket() throws {
+        let packet = makePacket(payload: makePayload(count: 384))
+        let request = BLEOutboundFragmentTransferRequest(
+            packet: packet,
+            pad: false,
+            maxChunk: 128,
+            directedPeer: nil,
+            transferId: nil
+        )
+
+        let plan = try #require(BLEOutboundFragmentPlanner.makePlan(
+            for: request,
+            defaultChunkSize: 256,
+            bleMaxMTU: 512,
+            fragmentID: Data(repeating: 0xA1, count: 8)
+        ))
+        let headers = try plan.fragmentPackets.map { try #require(BLEFragmentHeader(packet: $0)) }
+        let reassembled = headers.reduce(into: Data()) { data, header in
+            data.append(header.fragmentData)
+        }
+        let decoded = try #require(BinaryProtocol.decode(reassembled))
+
+        #expect(plan.fragmentVersion == 1)
+        #expect(plan.chunkSize == 128)
+        #expect(plan.spacingMs == TransportConfig.bleFragmentSpacingMs)
+        #expect(headers.map(\.index) == Array(0..<headers.count))
+        #expect(decoded.type == packet.type)
+        #expect(decoded.payload == packet.payload)
+        #expect(plan.fragmentPackets.allSatisfy { $0.recipientID == nil })
+    }
+
+    @Test("directed fragments target the directed peer and use directed pacing")
+    func directedFragmentsUseDirectedRecipientAndSpacing() throws {
+        let directedPeer = PeerID(str: "8877665544332211")
+        let packet = makePacket(payload: makePayload(count: 256))
+        let request = BLEOutboundFragmentTransferRequest(
+            packet: packet,
+            pad: false,
+            maxChunk: 96,
+            directedPeer: directedPeer,
+            transferId: nil
+        )
+
+        let plan = try #require(BLEOutboundFragmentPlanner.makePlan(
+            for: request,
+            defaultChunkSize: 256,
+            bleMaxMTU: 512,
+            fragmentID: Data(repeating: 0xB2, count: 8)
+        ))
+
+        #expect(plan.spacingMs == TransportConfig.bleFragmentSpacingDirectedMs)
+        #expect(plan.fragmentPackets.allSatisfy { $0.recipientID == Data(hexString: directedPeer.id) })
+    }
+
+    @Test("route-aware fragments use version two and route-sized chunking")
+    func routeAwareFragmentsUseVersionTwoAndRouteSizedChunking() throws {
+        let route = [
+            Data([0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17]),
+            Data([0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27])
+        ]
+        let packet = makePacket(payload: makePayload(count: 192), route: route, isRSR: true)
+        let request = BLEOutboundFragmentTransferRequest(
+            packet: packet,
+            pad: false,
+            maxChunk: nil,
+            directedPeer: nil,
+            transferId: nil
+        )
+
+        let plan = try #require(BLEOutboundFragmentPlanner.makePlan(
+            for: request,
+            defaultChunkSize: 256,
+            bleMaxMTU: 128,
+            fragmentID: Data(repeating: 0xC3, count: 8)
+        ))
+        let firstHeader = try #require(BLEFragmentHeader(packet: plan.fragmentPackets[0]))
+
+        #expect(plan.fragmentVersion == 2)
+        #expect(plan.chunkSize == 64)
+        #expect(firstHeader.fragmentData.count <= 64)
+        #expect(plan.fragmentPackets.allSatisfy { $0.route == route && $0.isRSR })
+    }
+
+    @Test("invalid fragment IDs do not produce a plan")
+    func invalidFragmentIDReturnsNil() {
+        let packet = makePacket(payload: makePayload(count: 128))
+        let request = BLEOutboundFragmentTransferRequest(
+            packet: packet,
+            pad: false,
+            maxChunk: nil,
+            directedPeer: nil,
+            transferId: nil
+        )
+
+        #expect(BLEOutboundFragmentPlanner.makePlan(
+            for: request,
+            defaultChunkSize: 256,
+            bleMaxMTU: 512,
+            fragmentID: Data(repeating: 0x00, count: 7)
+        ) == nil)
+    }
+
+    private func makePacket(
+        payload: Data,
+        route: [Data]? = nil,
+        isRSR: Bool = false
+    ) -> BitchatPacket {
+        BitchatPacket(
+            type: MessageType.message.rawValue,
+            senderID: Data([0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77]),
+            recipientID: nil,
+            timestamp: 0x0102030405,
+            payload: payload,
+            signature: nil,
+            ttl: 3,
+            route: route,
+            isRSR: isRSR
+        )
+    }
+
+    private func makePayload(count: Int, seed: UInt64 = 0xABCD_1234) -> Data {
+        var state = seed
+        return Data((0..<count).map { _ in
+            state = state &* 6364136223846793005 &+ 1442695040888963407
+            return UInt8(truncatingIfNeeded: state >> 32)
+        })
+    }
+}
@@ -0,0 +1,111 @@
+import BitFoundation
+import Foundation
+import Testing
+@testable import bitchat
+
+@Suite("BLE peer registry tests")
+struct BLEPeerRegistryTests {
+    @Test("upserted announces track new, reconnect, and rename transitions")
+    func upsertVerifiedAnnounceTracksTransitions() {
+        var registry = BLEPeerRegistry()
+        let peerID = PeerID(str: "1122334455667788")
+        let firstSeen = Date(timeIntervalSince1970: 100)
+
+        let first = registry.upsertVerifiedAnnounce(
+            peerID: peerID,
+            nickname: "alice",
+            noisePublicKey: Data([1, 2, 3]),
+            signingPublicKey: Data([4, 5, 6]),
+            isConnected: true,
+            now: firstSeen
+        )
+
+        #expect(first.isNewPeer)
+        #expect(!first.wasDisconnected)
+        #expect(first.previousNickname == nil)
+        #expect(registry.connectedPeerIDs == [peerID])
+        #expect(registry.nickname(for: peerID, connectedOnly: true) == "alice")
+
+        registry.markDisconnected(peerID)
+        let reconnect = registry.upsertVerifiedAnnounce(
+            peerID: peerID,
+            nickname: "alice-renamed",
+            noisePublicKey: Data([1, 2, 3]),
+            signingPublicKey: Data([4, 5, 6]),
+            isConnected: true,
+            now: firstSeen.addingTimeInterval(1)
+        )
+
+        #expect(!reconnect.isNewPeer)
+        #expect(reconnect.wasDisconnected)
+        #expect(reconnect.previousNickname == "alice")
+        #expect(registry.info(for: peerID)?.nickname == "alice-renamed")
+    }
+
+    @Test("reachability keeps recent verified offline peers only when mesh is attached")
+    func reachabilityRequiresMeshAttachmentForOfflinePeers() {
+        let offlinePeer = PeerID(str: "1122334455667788")
+        let connectedPeer = PeerID(str: "8877665544332211")
+        let now = Date()
+
+        var isolatedRegistry = BLEPeerRegistry()
+        isolatedRegistry.upsert(BLEPeerInfo(
+            peerID: offlinePeer,
+            nickname: "offline",
+            isConnected: false,
+            noisePublicKey: nil,
+            signingPublicKey: nil,
+            isVerifiedNickname: true,
+            lastSeen: now
+        ))
+
+        #expect(!isolatedRegistry.isReachable(offlinePeer, now: now))
+
+        var attachedRegistry = isolatedRegistry
+        attachedRegistry.upsert(BLEPeerInfo(
+            peerID: connectedPeer,
+            nickname: "connected",
+            isConnected: true,
+            noisePublicKey: nil,
+            signingPublicKey: nil,
+            isVerifiedNickname: true,
+            lastSeen: now
+        ))
+
+        #expect(attachedRegistry.isReachable(offlinePeer, now: now))
+    }
+
+    @Test("connectivity reconciliation disconnects inactive peers and prunes expired offline peers")
+    func reconcileConnectivityUpdatesAndPrunesPeerState() {
+        var registry = BLEPeerRegistry()
+        let inactiveConnectedPeer = PeerID(str: "1122334455667788")
+        let expiredOfflinePeer = PeerID(str: "8877665544332211")
+        let now = Date()
+
+        registry.upsert(BLEPeerInfo(
+            peerID: inactiveConnectedPeer,
+            nickname: "inactive",
+            isConnected: true,
+            noisePublicKey: nil,
+            signingPublicKey: nil,
+            isVerifiedNickname: true,
+            lastSeen: now.addingTimeInterval(-TransportConfig.blePeerInactivityTimeoutSeconds - 1)
+        ))
+        registry.upsert(BLEPeerInfo(
+            peerID: expiredOfflinePeer,
+            nickname: "expired",
+            isConnected: false,
+            noisePublicKey: nil,
+            signingPublicKey: nil,
+            isVerifiedNickname: true,
+            lastSeen: .distantPast
+        ))
+
+        let changes = registry.reconcileConnectivity(now: now, linkStates: [:])
+
+        #expect(changes.disconnectedPeerIDs == [inactiveConnectedPeer])
+        #expect(changes.removedPeers.map(\.peerID) == [expiredOfflinePeer])
+        #expect(registry.info(for: inactiveConnectedPeer)?.isConnected == false)
+        #expect(registry.info(for: expiredOfflinePeer) == nil)
+    }
+}
@@ -0,0 +1,78 @@
+import BitFoundation
+import Foundation
+import Testing
+@testable import bitchat
+
+@Suite("BLE peer sender display name tests")
+struct BLEPeerSenderDisplayNameTests {
+    @Test("local peer resolves to local nickname")
+    func localPeerUsesLocalNickname() {
+        let local = PeerID(str: "1122334455667788")
+
+        #expect(BLEPeerSenderDisplayName.resolveKnownPeer(
+            peerID: local,
+            localPeerID: local,
+            localNickname: "me",
+            peers: [:],
+            allowConnectedUnverified: false
+        ) == "me")
+    }
+
+    @Test("verified nickname collisions add peer suffix")
+    func verifiedCollisionAddsSuffix() {
+        let local = PeerID(str: "1122334455667788")
+        let peer = PeerID(str: "8877665544332211")
+        let peers = [
+            peer: makeInfo(peerID: peer, nickname: "sam", isConnected: false, isVerifiedNickname: true)
+        ]
+
+        #expect(BLEPeerSenderDisplayName.resolveKnownPeer(
+            peerID: peer,
+            localPeerID: local,
+            localNickname: "sam",
+            peers: peers,
+            allowConnectedUnverified: false
+        ) == "sam#8877")
+    }
+
+    @Test("connected unverified fallback is opt in")
+    func connectedUnverifiedFallbackIsOptIn() {
+        let local = PeerID(str: "1122334455667788")
+        let peer = PeerID(str: "8877665544332211")
+        let peers = [
+            peer: makeInfo(peerID: peer, nickname: "", isConnected: true, isVerifiedNickname: false)
+        ]
+
+        #expect(BLEPeerSenderDisplayName.resolveKnownPeer(
+            peerID: peer,
+            localPeerID: local,
+            localNickname: "me",
+            peers: peers,
+            allowConnectedUnverified: false
+        ) == nil)
+        #expect(BLEPeerSenderDisplayName.resolveKnownPeer(
+            peerID: peer,
+            localPeerID: local,
+            localNickname: "me",
+            peers: peers,
+            allowConnectedUnverified: true
+        ) == "anon8877")
+    }
+
+    private func makeInfo(
+        peerID: PeerID,
+        nickname: String,
+        isConnected: Bool,
+        isVerifiedNickname: Bool
+    ) -> BLEPeerInfo {
+        BLEPeerInfo(
+            peerID: peerID,
+            nickname: nickname,
+            isConnected: isConnected,
+            noisePublicKey: nil,
+            signingPublicKey: nil,
+            isVerifiedNickname: isVerifiedNickname,
+            lastSeen: Date(timeIntervalSince1970: 0)
+        )
+    }
+}
@@ -0,0 +1,105 @@
+import BitFoundation
+import Foundation
+import Testing
+@testable import bitchat
+
+@Suite("BLE receive pipeline tests")
+struct BLEReceivePipelineTests {
+    @Test("context includes sender, type-scoped message ID, and logging policy")
+    func contextBuildsTypeScopedMessageID() {
+        let sender = PeerID(str: "1122334455667788")
+        let local = PeerID(str: "8877665544332211")
+        let packet = makePacket(type: .message, sender: sender, timestamp: 1234)
+
+        let context = BLEReceivePipeline.context(for: packet, localPeerID: local)
+
+        #expect(context.senderID == sender)
+        #expect(context.messageID == "\(sender)-1234-\(MessageType.message.rawValue)")
+        #expect(context.messageType == .message)
+        #expect(context.shouldDeduplicate)
+        #expect(context.logsHandlingDetails)
+    }
+
+    @Test("fragments and self sync replays bypass global deduplication")
+    func contextBypassesDeduplicationForFragmentsAndSelfSyncReplay() {
+        let local = PeerID(str: "1122334455667788")
+        let remote = PeerID(str: "8877665544332211")
+
+        let fragment = BLEReceivePipeline.context(
+            for: makePacket(type: .fragment, sender: remote),
+            localPeerID: local
+        )
+        let selfReplay = BLEReceivePipeline.context(
+            for: makePacket(type: .message, sender: local, ttl: 0),
+            localPeerID: local
+        )
+
+        #expect(!fragment.shouldDeduplicate)
+        #expect(!selfReplay.shouldDeduplicate)
+    }
+
+    @Test("dense duplicate traffic cancels pending relays but sparse traffic does not")
+    func duplicateRelayCancellationUsesGraphDensity() {
+        #expect(!BLEReceivePipeline.shouldCancelScheduledRelayForDuplicate(connectedPeerCount: 2))
+        #expect(BLEReceivePipeline.shouldCancelScheduledRelayForDuplicate(connectedPeerCount: 3))
+    }
+
+    @Test("relay decision maps packet context and suppresses local recipient traffic")
+    func relayDecisionSuppressesLocalRecipientTraffic() {
+        let sender = PeerID(str: "1122334455667788")
+        let local = PeerID(str: "8877665544332211")
+        let packet = makePacket(
+            type: .noiseEncrypted,
+            sender: sender,
+            recipient: local,
+            ttl: 7
+        )
+
+        let decision = BLEReceivePipeline.relayDecision(
+            for: packet,
+            senderID: sender,
+            localPeerID: local,
+            degree: 3,
+            highDegreeThreshold: TransportConfig.bleHighDegreeThreshold
+        )
+
+        #expect(!decision.shouldRelay)
+    }
+
+    @Test("recent traffic tracker prunes by count and time window")
+    func recentTrafficTrackerPrunesByCountAndWindow() {
+        var tracker = BLERecentTrafficTracker()
+        let now = Date(timeIntervalSince1970: 1_000)
+
+        tracker.recordPacket(at: now.addingTimeInterval(-TransportConfig.bleRecentPacketWindowSeconds - 1))
+        #expect(!tracker.hasTraffic(within: TransportConfig.bleRecentPacketWindowSeconds, now: now))
+
+        for index in 0...TransportConfig.bleRecentPacketWindowMaxCount {
+            tracker.recordPacket(at: now.addingTimeInterval(Double(index) * 0.001))
+        }
+
+        #expect(tracker.count == TransportConfig.bleRecentPacketWindowMaxCount)
+        #expect(tracker.hasTraffic(within: 1.0, now: now.addingTimeInterval(0.1)))
+
+        tracker.removeAll()
+        #expect(tracker.count == 0)
+    }
+
+    private func makePacket(
+        type: MessageType,
+        sender: PeerID,
+        recipient: PeerID? = nil,
+        timestamp: UInt64 = 1,
+        ttl: UInt8 = 7
+    ) -> BitchatPacket {
+        BitchatPacket(
+            type: type.rawValue,
+            senderID: Data(hexString: sender.id) ?? Data(),
+            recipientID: recipient.flatMap { Data(hexString: $0.id) },
+            timestamp: timestamp,
+            payload: Data([0x01, 0x02]),
+            signature: nil,
+            ttl: ttl
+        )
+    }
+}
@@ -0,0 +1,61 @@
+import Foundation
+import Testing
+@testable import bitchat
+
+@Suite("BLE subscription announce limiter tests")
+struct BLESubscriptionAnnounceLimiterTests {
+    @Test("first subscription is allowed and repeated subscriptions are rate limited")
+    func repeatedSubscriptionsAreRateLimited() {
+        var limiter = BLESubscriptionAnnounceLimiter()
+        let centralID = "central-a"
+        let now = Date(timeIntervalSince1970: 100)
+
+        #expect(limiter.decision(for: centralID, now: now) == .allowed)
+        #expect(limiter.trackedCentralCount == 1)
+
+        let second = limiter.decision(for: centralID, now: now.addingTimeInterval(0.1))
+        #expect(second == .rateLimited(
+            backoffSeconds: TransportConfig.bleSubscriptionRateLimitMinSeconds,
+            attemptCount: 1,
+            suppressAnnounce: false
+        ))
+    }
+
+    @Test("rapid subscription attempts eventually suppress announces")
+    func rapidAttemptsSuppressAnnouncesAtThreshold() {
+        var limiter = BLESubscriptionAnnounceLimiter()
+        let centralID = "central-a"
+        let now = Date(timeIntervalSince1970: 100)
+
+        #expect(limiter.decision(for: centralID, now: now) == .allowed)
+
+        var decision = BLESubscriptionAnnounceDecision.allowed
+        for attempt in 2...TransportConfig.bleSubscriptionRateLimitMaxAttempts {
+            decision = limiter.decision(
+                for: centralID,
+                now: now.addingTimeInterval(Double(attempt) * 0.01)
+            )
+        }
+
+        if case let .rateLimited(_, _, suppressAnnounce) = decision {
+            #expect(suppressAnnounce)
+        } else {
+            Issue.record("Expected rate-limited decision at suppression threshold")
+        }
+    }
+
+    @Test("stale limiter entries are pruned on the next decision")
+    func staleEntriesArePruned() {
+        var limiter = BLESubscriptionAnnounceLimiter()
+        let staleCentralID = "central-a"
+        let freshCentralID = "central-b"
+        let now = Date(timeIntervalSince1970: 100)
+
+        #expect(limiter.decision(for: staleCentralID, now: now) == .allowed)
+        #expect(limiter.trackedCentralCount == 1)
+
+        let afterWindow = now.addingTimeInterval(TransportConfig.bleSubscriptionRateLimitWindowSeconds + 1)
+        #expect(limiter.decision(for: freshCentralID, now: afterWindow) == .allowed)
+        #expect(limiter.trackedCentralCount == 1)
+    }
+}