Initial commit: NetworkCity — network traffic as a neon city

A native macOS network monitor that renders live traffic as a top-down neon city: your Mac is downtown, remote orgs are glowing districts, and traffic is cars of light driving the roads. Architecture: - NetworkCityCore: swappable data layer behind a ConnectionSource protocol (nettop-backed today), plus pure/tested logic — traffic diffing, org classification (reverse-DNS + CIDR), traffic classes, hub-and-spoke expansion policy, label anti-overlap, and latency→distance layout. - NetworkCityApp: SwiftUI + SpriteKit city — auto-expanding districts, protocol-coloured cars, click-to-inspect panel, and latency-as-distance (districts glide to their measured RTT). - nettop-probe: CLI proof of the data layer. 44 tests passing. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-13 08:43:32 -07:00
commit c08fc277a9
33 changed files with 2499 additions and 0 deletions
@@ -0,0 +1,44 @@
+import XCTest
+@testable import NetworkCityCore
+
+final class TrafficDifferTests: XCTestCase {
+
+    private func conn(_ host: String, in bIn: UInt64, out bOut: UInt64) -> Connection {
+        Connection(
+            proto: .tcp4,
+            local: Endpoint(host: "192.168.1.2", port: 5000),
+            remote: Endpoint(host: host, port: 443),
+            bytesIn: bIn, bytesOut: bOut,
+            processName: "test", pid: 1
+        )
+    }
+
+    func testFirstSnapshotYieldsNoDeltas() {
+        let differ = TrafficDiffer()
+        let t0 = Date(timeIntervalSince1970: 1000)
+        let deltas = differ.ingest(ConnectionSnapshot(timestamp: t0, connections: [conn("1.1.1.1", in: 100, out: 50)]))
+        XCTAssertTrue(deltas.isEmpty)   // need two readings to know a rate
+    }
+
+    func testComputesDeltaAndRate() {
+        let differ = TrafficDiffer()
+        let t0 = Date(timeIntervalSince1970: 1000)
+        let t1 = Date(timeIntervalSince1970: 1002)   // +2s
+        _ = differ.ingest(ConnectionSnapshot(timestamp: t0, connections: [conn("1.1.1.1", in: 100, out: 50)]))
+        let deltas = differ.ingest(ConnectionSnapshot(timestamp: t1, connections: [conn("1.1.1.1", in: 1124, out: 50)]))
+
+        XCTAssertEqual(deltas.count, 1)
+        XCTAssertEqual(deltas[0].bytesInDelta, 1024)
+        XCTAssertEqual(deltas[0].bytesOutDelta, 0)
+        XCTAssertEqual(deltas[0].inBytesPerSec, 512, accuracy: 0.001)   // 1024 / 2s
+    }
+
+    func testCounterResetTreatedAsZero() {
+        let differ = TrafficDiffer()
+        let t0 = Date(timeIntervalSince1970: 1000)
+        let t1 = Date(timeIntervalSince1970: 1002)
+        _ = differ.ingest(ConnectionSnapshot(timestamp: t0, connections: [conn("1.1.1.1", in: 9999, out: 0)]))
+        let deltas = differ.ingest(ConnectionSnapshot(timestamp: t1, connections: [conn("1.1.1.1", in: 10, out: 0)]))
+        XCTAssertTrue(deltas.isEmpty)   // reused tuple, counter dropped -> no phantom delta
+    }
+}