From 7f5b4c089e842f88edb829809453088521d6cf52 Mon Sep 17 00:00:00 2001
From: Shadowbroker <43977454+BigBodyCobain@users.noreply.github.com>
Date: Thu, 20 Aug 2026 21:00:00 -0600
Subject: [PATCH] test(layers): cover backend restart reconciliation

---
 .../lib/layerBackendReconciliation.test.ts    | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 frontend/src/__tests__/lib/layerBackendReconciliation.test.ts

diff --git a/frontend/src/__tests__/lib/layerBackendReconciliation.test.ts b/frontend/src/__tests__/lib/layerBackendReconciliation.test.ts
new file mode 100644
index 0000000..d14d0e6
--- /dev/null
+++ b/frontend/src/__tests__/lib/layerBackendReconciliation.test.ts
@@ -0,0 +1,86 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+describe('layer backend reconciliation', () => {
+  beforeEach(() => {
+    vi.resetModules();
+    localStorage.clear();
+  });
+
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    localStorage.clear();
+  });
+
+  it('replays saved operator toggles when a restarted backend is back at defaults', async () => {
+    const prefs = await import('@/lib/layerPreferences');
+    const desired = {
+      ...prefs.getDefaultActiveLayers(),
+      cctv: true,
+      datacenters: true,
+      power_plants: true,
+    };
+    prefs.saveActiveLayers(desired);
+
+    const fetchMock = vi
+      .fn()
+      .mockResolvedValueOnce({
+        ok: true,
+        json: async () => ({ layers: prefs.getDefaultActiveLayers(), overrides: {} }),
+      })
+      .mockResolvedValueOnce({ ok: true });
+    vi.stubGlobal('fetch', fetchMock);
+
+    await expect(prefs.reconcileActiveLayersWithBackend()).resolves.toBe('synced');
+    expect(fetchMock).toHaveBeenCalledTimes(2);
+    expect(fetchMock.mock.calls[1]?.[1]?.method).toBe('POST');
+    const posted = JSON.parse(String(fetchMock.mock.calls[1]?.[1]?.body));
+    expect(posted.layers.cctv).toBe(true);
+    expect(posted.layers.datacenters).toBe(true);
+    expect(posted.layers.power_plants).toBe(true);
+  });
+
+  it('does not fight a non-default backend state after a healthy connection', async () => {
+    const prefs = await import('@/lib/layerPreferences');
+    const desired = { ...prefs.getDefaultActiveLayers(), cctv: true };
+    prefs.saveActiveLayers(desired);
+    const otherClientState = { ...desired, datacenters: true };
+
+    const fetchMock = vi
+      .fn()
+      .mockResolvedValueOnce({
+        ok: true,
+        json: async () => ({ layers: desired, overrides: {} }),
+      })
+      .mockResolvedValueOnce({
+        ok: true,
+        json: async () => ({ layers: otherClientState, overrides: {} }),
+      });
+    vi.stubGlobal('fetch', fetchMock);
+
+    await expect(prefs.reconcileActiveLayersWithBackend()).resolves.toBe('noop');
+    await expect(prefs.reconcileActiveLayersWithBackend()).resolves.toBe('noop');
+    expect(fetchMock).toHaveBeenCalledTimes(2);
+    expect(fetchMock.mock.calls.every((call) => call[1]?.method !== 'POST')).toBe(true);
+  });
+
+  it('retries saved state after an observed backend outage', async () => {
+    const prefs = await import('@/lib/layerPreferences');
+    const desired = { ...prefs.getDefaultActiveLayers(), cctv: true };
+    prefs.saveActiveLayers(desired);
+
+    const fetchMock = vi
+      .fn()
+      .mockRejectedValueOnce(new Error('backend restarting'))
+      .mockResolvedValueOnce({
+        ok: true,
+        json: async () => ({ layers: prefs.getDefaultActiveLayers(), overrides: {} }),
+      })
+      .mockResolvedValueOnce({ ok: true });
+    vi.stubGlobal('fetch', fetchMock);
+
+    await expect(prefs.reconcileActiveLayersWithBackend()).resolves.toBe('offline');
+    await expect(prefs.reconcileActiveLayersWithBackend()).resolves.toBe('synced');
+    expect(fetchMock).toHaveBeenCalledTimes(3);
+    expect(fetchMock.mock.calls[2]?.[1]?.method).toBe('POST');
+  });
+});