Fix dedupe for frontend raw packet delivery

frontend/src/test/rawPacketIdentity.test.ts

@@ -0,0 +1,79 @@
+import { describe, expect, it } from 'vitest';
+import type { RawPacket } from '../types';
+import { appendRawPacketUnique, getRawPacketObservationKey } from '../utils/rawPacketIdentity';
+
+function createPacket(overrides: Partial<RawPacket> = {}): RawPacket {
+  return {
+    id: 1,
+    timestamp: 1700000000,
+    data: '010203',
+    payload_type: 'ACK',
+    snr: null,
+    rssi: null,
+    decrypted: false,
+    decrypted_info: null,
+    ...overrides,
+  };
+}
+
+describe('getRawPacketObservationKey', () => {
+  it('uses observation_id when present', () => {
+    const packet = createPacket({ id: 99, observation_id: 7 });
+    expect(getRawPacketObservationKey(packet)).toBe('obs-7');
+  });
+
+  it('falls back to db id when observation_id is missing', () => {
+    const packet = createPacket({ id: 42 });
+    expect(getRawPacketObservationKey(packet)).toBe('db-42');
+  });
+});
+
+describe('appendRawPacketUnique', () => {
+  it('keeps path-diverse observations with same db id', () => {
+    const first = createPacket({ id: 5, observation_id: 100, data: 'aa' });
+    const second = createPacket({ id: 5, observation_id: 101, data: 'bb' });
+
+    const afterFirst = appendRawPacketUnique([], first, 500);
+    const afterSecond = appendRawPacketUnique(afterFirst, second, 500);
+
+    expect(afterSecond).toHaveLength(2);
+    expect(afterSecond[0].observation_id).toBe(100);
+    expect(afterSecond[1].observation_id).toBe(101);
+  });
+
+  it('drops exact duplicate observations', () => {
+    const packet = createPacket({ id: 5, observation_id: 100 });
+
+    const afterFirst = appendRawPacketUnique([], packet, 500);
+    const afterSecond = appendRawPacketUnique(afterFirst, packet, 500);
+
+    expect(afterSecond).toHaveLength(1);
+  });
+
+  it('dedupes by db id when observation_id is absent', () => {
+    const first = createPacket({ id: 11, observation_id: undefined });
+    const second = createPacket({ id: 11, observation_id: undefined, timestamp: 1700000001 });
+
+    const afterFirst = appendRawPacketUnique([], first, 500);
+    const afterSecond = appendRawPacketUnique(afterFirst, second, 500);
+
+    expect(afterSecond).toHaveLength(1);
+  });
+
+  it('enforces max packet cap', () => {
+    const packets = [
+      createPacket({ id: 1, observation_id: 1 }),
+      createPacket({ id: 2, observation_id: 2 }),
+      createPacket({ id: 3, observation_id: 3 }),
+    ];
+
+    let state: RawPacket[] = [];
+    state = appendRawPacketUnique(state, packets[0], 2);
+    state = appendRawPacketUnique(state, packets[1], 2);
+    state = appendRawPacketUnique(state, packets[2], 2);
+
+    expect(state).toHaveLength(2);
+    expect(state[0].observation_id).toBe(2);
+    expect(state[1].observation_id).toBe(3);
+  });
+});