feat(devices): arp-scan parser + randomized-MAC detection

tests/infra/scan.test.js

@@ -0,0 +1,35 @@
+// tests/infra/scan.test.js
+import { describe, it, expect } from 'vitest';
+import { isRandomizedMac, parseArpScan, runScan } from '../../lib/infra/scan.js';
+
+const SAMPLE = [
+  'Interface: eth0, type: EN10MB, MAC: bc:24:11:9b:b7:3a, IPv4: 192.168.1.216',
+  'Starting arp-scan 1.10.0',
+  '192.168.1.13\tbc:a5:11:3e:06:88\tNetgear',
+  '192.168.1.171\t5a:da:61:7a:0f:12\t(Unknown)',
+  '192.168.1.1\t44:A5:6E:68:D0:E9\tNetgear Inc.',
+  'garbage line that is not a host',
+  '',
+  '3 packets received by filter, 0 packets dropped'
+].join('\n');
+
+describe('scan parsing', () => {
+  it('isRandomizedMac flags locally-administered MACs', () => {
+    expect(isRandomizedMac('5a:da:61:7a:0f:12')).toBe(true);   // 0x5a & 0x02
+    expect(isRandomizedMac('bc:a5:11:3e:06:88')).toBe(false);  // 0xbc & 0x02 == 0
+    expect(isRandomizedMac('44:A5:6E:68:D0:E9')).toBe(false);
+  });
+
+  it('parseArpScan keeps only host lines, lowercases MAC, flags randomized', () => {
+    const rows = parseArpScan(SAMPLE);
+    expect(rows).toHaveLength(3);
+    expect(rows[0]).toEqual({ ip: '192.168.1.13', mac: 'bc:a5:11:3e:06:88', vendor: 'Netgear', randomized: false });
+    expect(rows[1]).toEqual({ ip: '192.168.1.171', mac: '5a:da:61:7a:0f:12', vendor: '(Unknown)', randomized: true });
+    expect(rows[2].mac).toBe('44:a5:6e:68:d0:e9'); // lowercased
+  });
+
+  it('runScan parses the injected exec stdout', async () => {
+    const rows = await runScan({ exec: async () => ({ stdout: SAMPLE }) });
+    expect(rows.map(r => r.ip)).toEqual(['192.168.1.13', '192.168.1.171', '192.168.1.1']);
+  });
+});