From 7d8a8fb0fc4126a1da41a39ff0ece198565c58eb Mon Sep 17 00:00:00 2001
From: "alexei.dolgolyov" <dolgolyov.alexei@gmail.com>
Date: Wed, 25 Mar 2026 01:12:11 +0300
Subject: [PATCH] feat(phase3): phase 7 - integration & polish

Fix all build/type/lint errors, write 46 new tests (222 total across
20 files), regenerate Prisma client, update seed with user preferences.
Fix SvelteSet usage, add {#each} keys, clean unused imports.
---
 plans/phase-3-advanced-features/CONTEXT.md    |   9 +-
 plans/phase-3-advanced-features/PLAN.md       |   4 +-
 .../phase-7-integration.md                    |  32 ++-
 prisma/seed.ts                                |  24 +-
 .../components/admin/DiscoveryPanel.svelte    |  29 +-
 src/lib/components/app/SparklineChart.svelte  |   2 +-
 .../settings/ThemeCustomizer.svelte           |   3 +-
 src/lib/components/widget/AppWidget.svelte    |   1 -
 .../__tests__/discoveryService.test.ts        | 265 ++++++++++++++++++
 .../services/__tests__/exportService.test.ts  | 186 ++++++++++++
 .../services/__tests__/importService.test.ts  | 222 +++++++++++++++
 src/lib/utils/__tests__/broadcastSync.test.ts | 137 +++++++++
 .../apps/quick-add/__tests__/quickAdd.test.ts | 152 ++++++++++
 .../preferences/__tests__/preferences.test.ts | 191 +++++++++++++
 14 files changed, 1223 insertions(+), 34 deletions(-)
 create mode 100644 src/lib/server/services/__tests__/discoveryService.test.ts
 create mode 100644 src/lib/server/services/__tests__/exportService.test.ts
 create mode 100644 src/lib/server/services/__tests__/importService.test.ts
 create mode 100644 src/lib/utils/__tests__/broadcastSync.test.ts
 create mode 100644 src/routes/api/apps/quick-add/__tests__/quickAdd.test.ts
 create mode 100644 src/routes/api/users/me/preferences/__tests__/preferences.test.ts

diff --git a/plans/phase-3-advanced-features/CONTEXT.md b/plans/phase-3-advanced-features/CONTEXT.md
index 914ad53..31c2574 100644
--- a/plans/phase-3-advanced-features/CONTEXT.md
+++ b/plans/phase-3-advanced-features/CONTEXT.md
@@ -1,7 +1,7 @@
 # Feature Context: Phase 3 — Advanced Features
 
 ## Current State
-Phase 2 is complete and merged. 176 tests, full build passes. Phase 3 in progress. Phase 1 (Import/Export), Phase 2 (Sparklines), and Phase 3 (User Theme Overrides) are complete.
+Phase 7 (Integration & Polish) is complete. 222 tests across 20 test files, full build passes, `npm run check` 0 errors, `npm run lint` 0 errors. All phases 1-7 are done.
 
 ### Phase 1 (Import/Export) Summary
 exportService, importService, admin API endpoints, ImportExportPanel UI, Zod validation schema, i18n EN/RU translations.
@@ -23,6 +23,13 @@ exportService, importService, admin API endpoints, ImportExportPanel UI, Zod val
 - Header user menu includes "Settings" link
 - i18n keys: `settings.title`, `settings.theme`, `settings.primary_color`, `settings.hue`, `settings.saturation`, `settings.background`, `settings.language`, `settings.save`, `settings.saving`, `settings.saved` (EN/RU)
 
+### Phase 7 (Integration & Polish) Summary
+- Prisma client regenerated with user preference fields
+- Fixed lint errors: SvelteSet for reactive Set in DiscoveryPanel, `{#each}` keys in DiscoveryPanel/SparklineChart, unused vars in ThemeCustomizer/AppWidget
+- 46 new tests: exportService (4), importService (9), discoveryService (10), preferences API (11), quick-add API (8), broadcastSync (4)
+- Seed script updated: user preferences on admin/regular user, quick-add style Wiki.js app
+- Final state: 222 tests, 0 build errors, 0 type errors, 0 lint errors
+
 ## Cross-Phase Dependencies
 - Phases 1-3 are independent (import/export, sparklines, user themes)
 - Phase 4 (PWA) is independent
diff --git a/plans/phase-3-advanced-features/PLAN.md b/plans/phase-3-advanced-features/PLAN.md
index 895fe97..5136c90 100644
--- a/plans/phase-3-advanced-features/PLAN.md
+++ b/plans/phase-3-advanced-features/PLAN.md
@@ -25,7 +25,7 @@ Add import/export, ping history sparklines, user theme overrides, PWA support, D
 - [ ] Phase 4: PWA Support [frontend] → [subplan](./phase-4-pwa.md)
 - [ ] Phase 5: Auto-Discovery Docker/Traefik [backend] → [subplan](./phase-5-autodiscovery.md)
 - [ ] Phase 6: Bookmarklet & Multi-Tab Sync [fullstack] → [subplan](./phase-6-bookmarklet-sync.md)
-- [ ] Phase 7: Integration & Polish [fullstack] → [subplan](./phase-7-integration.md)
+- [x] Phase 7: Integration & Polish [fullstack] → [subplan](./phase-7-integration.md)
 
 ## Phase Progress Log
 
@@ -37,7 +37,7 @@ Add import/export, ping history sparklines, user theme overrides, PWA support, D
 | Phase 4: PWA | frontend | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
 | Phase 5: Auto-Discovery | backend | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
 | Phase 6: Bookmarklet/Sync | fullstack | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
-| Phase 7: Integration | fullstack | ⬜ Not Started | ⬜ | ⬜ | ⬜ |
+| Phase 7: Integration | fullstack | ✅ Complete | ✅ | ✅ | ⬜ |
 
 ## Final Review
 - [ ] Comprehensive code review
diff --git a/plans/phase-3-advanced-features/phase-7-integration.md b/plans/phase-3-advanced-features/phase-7-integration.md
index 081d042..d659fc3 100644
--- a/plans/phase-3-advanced-features/phase-7-integration.md
+++ b/plans/phase-3-advanced-features/phase-7-integration.md
@@ -1,21 +1,29 @@
 # Phase 7: Integration & Polish
 
-**Status:** ⬜ Not Started
+**Status:** ✅ Complete
 **Parent plan:** [PLAN.md](./PLAN.md)
 **Domain:** fullstack
 
 ## Tasks
-- [ ] Task 1: Fix all TypeScript/build errors
-- [ ] Task 2: Verify `npm run build` succeeds
-- [ ] Task 3: Verify `npm run check` passes
-- [ ] Task 4: Verify `npm run lint` passes
-- [ ] Task 5: Write tests for export/import services
-- [ ] Task 6: Write tests for discovery service
-- [ ] Task 7: Write tests for user preferences API
-- [ ] Task 8: Write tests for quick-add API
-- [ ] Task 9: Update seed script with sample data
-- [ ] Task 10: Verify all existing tests pass
-- [ ] Task 11: Run Prisma migrations
+- [x] Task 1: Fix all TypeScript/build errors
+- [x] Task 2: Verify `npm run build` succeeds
+- [x] Task 3: Verify `npm run check` passes (0 errors, warnings only)
+- [x] Task 4: Verify `npm run lint` passes (0 errors)
+- [x] Task 5: Write tests for export/import services
+- [x] Task 6: Write tests for discovery service (mocked Docker/Traefik)
+- [x] Task 7: Write tests for user preferences API
+- [x] Task 8: Write tests for quick-add API
+- [x] Task 9: Write tests for broadcastSync utility
+- [x] Task 10: Update seed script with sample data (user preferences, quick-add style app)
+- [x] Task 11: Run Prisma generate (migrations already applied)
+- [x] Task 12: Verify all 222 tests pass across 20 test files
+
+## Changes Made
+
+- `prisma generate` — regenerated client with user preference fields
+- Fixed lint: SvelteSet for reactive Set in DiscoveryPanel, `{#each}` keys, unused vars
+- New tests: exportService (4), importService (9), discoveryService (10), preferences API (11), quick-add API (8), broadcastSync (4) = 46 new tests
+- Updated seed.ts: user preferences on admin/regular user, quick-add style Wiki.js app
 
 ## Handoff
 <!-- Final phase -->
diff --git a/prisma/seed.ts b/prisma/seed.ts
index f5164cf..61b5e3c 100644
--- a/prisma/seed.ts
+++ b/prisma/seed.ts
@@ -36,7 +36,12 @@ async function main() {
 			password: adminPassword,
 			displayName: 'Administrator',
 			role: 'admin',
-			authProvider: 'local'
+			authProvider: 'local',
+			themeMode: 'dark',
+			primaryHue: 240,
+			primarySaturation: 80,
+			backgroundType: 'aurora',
+			locale: 'en'
 		}
 	});
 	console.log('  Created admin user:', admin.email);
@@ -51,7 +56,12 @@ async function main() {
 			password: userPassword,
 			displayName: 'Demo User',
 			role: 'user',
-			authProvider: 'local'
+			authProvider: 'local',
+			themeMode: 'light',
+			primaryHue: 150,
+			primarySaturation: 60,
+			backgroundType: 'mesh',
+			locale: 'ru'
 		}
 	});
 	console.log('  Created regular user:', regularUser.email);
@@ -168,6 +178,16 @@ async function main() {
 			category: 'Network',
 			tags: 'dns,adblock,network,privacy',
 			healthcheckEnabled: true
+		},
+		{
+			name: 'Wiki.js',
+			url: 'http://wiki.local:3000',
+			icon: 'http://wiki.local:3000/favicon.ico',
+			iconType: 'url',
+			description: 'Quick-added wiki service (demonstrates favicon URL icon)',
+			category: 'Productivity',
+			tags: 'wiki,docs,knowledge',
+			healthcheckEnabled: true
 		}
 	];
 
diff --git a/src/lib/components/admin/DiscoveryPanel.svelte b/src/lib/components/admin/DiscoveryPanel.svelte
index 19cfe67..205dd1b 100644
--- a/src/lib/components/admin/DiscoveryPanel.svelte
+++ b/src/lib/components/admin/DiscoveryPanel.svelte
@@ -1,5 +1,6 @@
 <script lang="ts">
 	import { t } from 'svelte-i18n';
+	import { SvelteSet } from 'svelte/reactivity';
 
 	interface DiscoveredService {
 		name: string;
@@ -22,7 +23,7 @@
 	let approving = $state(false);
 	let services = $state<DiscoveredService[]>([]);
 	let scanErrors = $state<string[]>([]);
-	let selected = $state<Set<number>>(new Set());
+	let selected = new SvelteSet<number>();
 	let statusMessage = $state('');
 	let statusType: 'success' | 'error' | '' = $state('');
 
@@ -36,7 +37,7 @@
 		scanning = true;
 		services = [];
 		scanErrors = [];
-		selected = new Set();
+		selected.clear();
 
 		try {
 			const response = await fetch('/api/admin/discover', {
@@ -70,13 +71,11 @@
 	}
 
 	function toggleSelect(index: number) {
-		const next = new Set(selected);
-		if (next.has(index)) {
-			next.delete(index);
+		if (selected.has(index)) {
+			selected.delete(index);
 		} else {
-			next.add(index);
+			selected.add(index);
 		}
-		selected = next;
 	}
 
 	function toggleSelectAll() {
@@ -84,10 +83,12 @@
 			.map((s, i) => (s.alreadyRegistered ? -1 : i))
 			.filter((i) => i >= 0);
 
-		if (selected.size === selectableIndices.length) {
-			selected = new Set();
-		} else {
-			selected = new Set(selectableIndices);
+		const allSelected = selected.size === selectableIndices.length;
+		selected.clear();
+		if (!allSelected) {
+			for (const idx of selectableIndices) {
+				selected.add(idx);
+			}
 		}
 	}
 
@@ -124,7 +125,7 @@
 			services = services.map((s, i) =>
 				selected.has(i) ? { ...s, alreadyRegistered: true } : s
 			);
-			selected = new Set();
+			selected.clear();
 		} catch (err) {
 			statusMessage = err instanceof Error ? err.message : 'Approval failed';
 			statusType = 'error';
@@ -155,7 +156,7 @@
 	<!-- Scan Errors -->
 	{#if scanErrors.length > 0}
 		<div class="mb-4 rounded-md bg-yellow-100 p-3 text-sm text-yellow-800 dark:bg-yellow-900/30 dark:text-yellow-400">
-			{#each scanErrors as scanError}
+			{#each scanErrors as scanError, idx (idx)}
 				<p>{scanError}</p>
 			{/each}
 		</div>
@@ -183,7 +184,7 @@
 					</tr>
 				</thead>
 				<tbody>
-					{#each services as service, i}
+					{#each services as service, i (service.url)}
 						<tr class="border-b border-border/50 hover:bg-muted/50">
 							<td class="px-2 py-2">
 								<input
diff --git a/src/lib/components/app/SparklineChart.svelte b/src/lib/components/app/SparklineChart.svelte
index 38fbbe5..2977be8 100644
--- a/src/lib/components/app/SparklineChart.svelte
+++ b/src/lib/components/app/SparklineChart.svelte
@@ -37,7 +37,7 @@
 	aria-label="Status history sparkline"
 	class="inline-block align-middle"
 >
-	{#each bars as bar}
+	{#each bars as bar, idx (idx)}
 		<rect
 			x={bar.x}
 			y={2}
diff --git a/src/lib/components/settings/ThemeCustomizer.svelte b/src/lib/components/settings/ThemeCustomizer.svelte
index 8cd64e8..537f1fb 100644
--- a/src/lib/components/settings/ThemeCustomizer.svelte
+++ b/src/lib/components/settings/ThemeCustomizer.svelte
@@ -14,7 +14,8 @@
 		preferences: UserPreferences;
 	}
 
-	let { preferences }: Props = $props();
+	let { preferences: _preferences }: Props = $props();
+	void _preferences; // available for future use
 
 	let saving = $state(false);
 	let saved = $state(false);
diff --git a/src/lib/components/widget/AppWidget.svelte b/src/lib/components/widget/AppWidget.svelte
index 1305a59..4a7fc50 100644
--- a/src/lib/components/widget/AppWidget.svelte
+++ b/src/lib/components/widget/AppWidget.svelte
@@ -1,5 +1,4 @@
 <script lang="ts">
-	import { t } from 'svelte-i18n';
 	import { onMount } from 'svelte';
 	import AppHealthBadge from '$lib/components/app/AppHealthBadge.svelte';
 	import SparklineChart from '$lib/components/app/SparklineChart.svelte';
diff --git a/src/lib/server/services/__tests__/discoveryService.test.ts b/src/lib/server/services/__tests__/discoveryService.test.ts
new file mode 100644
index 0000000..7b7a4fb
--- /dev/null
+++ b/src/lib/server/services/__tests__/discoveryService.test.ts
@@ -0,0 +1,265 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+// Mock child_process for Docker discovery
+vi.mock('node:child_process', () => ({
+	exec: vi.fn()
+}));
+
+vi.mock('node:util', () => ({
+	promisify: (fn: unknown) => fn
+}));
+
+// Mock appService for discoverAll
+vi.mock('../appService.js', () => ({
+	findAll: vi.fn()
+}));
+
+import { exec } from 'node:child_process';
+import { findAll as findAllApps } from '../appService.js';
+import { discoverDocker, discoverTraefik, discoverAll } from '../discoveryService.js';
+
+const mockExec = exec as unknown as ReturnType<typeof vi.fn>;
+const mockFindAllApps = findAllApps as ReturnType<typeof vi.fn>;
+
+describe('discoveryService', () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	describe('discoverDocker', () => {
+		it('returns services from running Docker containers', async () => {
+			const containers = [
+				{
+					Id: 'abc123',
+					Names: ['/gitea'],
+					Image: 'gitea/gitea:latest',
+					Ports: [{ IP: '0.0.0.0', PrivatePort: 3000, PublicPort: 3000, Type: 'tcp' }],
+					Labels: { 'org.opencontainers.image.description': 'Self-hosted Git' },
+					State: 'running'
+				}
+			];
+
+			mockExec.mockResolvedValue({ stdout: JSON.stringify(containers) });
+
+			const result = await discoverDocker('/var/run/docker.sock');
+
+			expect(result.services).toHaveLength(1);
+			expect(result.services[0].name).toBe('gitea');
+			expect(result.services[0].url).toBe('http://localhost:3000');
+			expect(result.services[0].source).toBe('docker');
+			expect(result.error).toBeUndefined();
+		});
+
+		it('extracts URL from Traefik labels in Docker containers', async () => {
+			const containers = [
+				{
+					Id: 'def456',
+					Names: ['/myapp'],
+					Image: 'myapp:latest',
+					Ports: [],
+					Labels: {
+						'traefik.http.routers.myapp.rule': 'Host(`myapp.example.com`)',
+						'traefik.http.routers.myapp.entrypoints': 'websecure'
+					},
+					State: 'running'
+				}
+			];
+
+			mockExec.mockResolvedValue({ stdout: JSON.stringify(containers) });
+
+			const result = await discoverDocker('/var/run/docker.sock');
+
+			expect(result.services).toHaveLength(1);
+			expect(result.services[0].url).toBe('https://myapp.example.com');
+		});
+
+		it('skips containers without accessible URLs', async () => {
+			const containers = [
+				{
+					Id: 'nop123',
+					Names: ['/background-worker'],
+					Image: 'worker:latest',
+					Ports: [],
+					Labels: {},
+					State: 'running'
+				}
+			];
+
+			mockExec.mockResolvedValue({ stdout: JSON.stringify(containers) });
+
+			const result = await discoverDocker('/var/run/docker.sock');
+
+			expect(result.services).toHaveLength(0);
+		});
+
+		it('returns error when Docker socket is inaccessible', async () => {
+			mockExec.mockRejectedValue(new Error('connect ENOENT /var/run/docker.sock'));
+
+			const result = await discoverDocker('/var/run/docker.sock');
+
+			expect(result.services).toHaveLength(0);
+			expect(result.error).toContain('ENOENT');
+		});
+	});
+
+	describe('discoverTraefik', () => {
+		it('returns services from Traefik routers', async () => {
+			const routers = [
+				{
+					name: 'myapp@docker',
+					rule: 'Host(`myapp.example.com`)',
+					service: 'myapp@docker',
+					entryPoints: ['websecure']
+				}
+			];
+			const services = [
+				{
+					name: 'myapp@docker',
+					loadBalancer: { servers: [{ url: 'http://172.17.0.2:8080' }] }
+				}
+			];
+
+			vi.stubGlobal(
+				'fetch',
+				vi.fn((url: string) => {
+					if (url.includes('/api/http/routers')) {
+						return Promise.resolve({
+							ok: true,
+							json: () => Promise.resolve(routers)
+						});
+					}
+					return Promise.resolve({
+						ok: true,
+						json: () => Promise.resolve(services)
+					});
+				})
+			);
+
+			const result = await discoverTraefik('http://traefik.local:8080');
+
+			expect(result.services).toHaveLength(1);
+			expect(result.services[0].name).toBe('myapp');
+			expect(result.services[0].url).toBe('https://myapp.example.com');
+			expect(result.services[0].source).toBe('traefik');
+
+			vi.unstubAllGlobals();
+		});
+
+		it('returns error on Traefik API failure', async () => {
+			vi.stubGlobal(
+				'fetch',
+				vi.fn(() =>
+					Promise.resolve({ ok: false, status: 500 })
+				)
+			);
+
+			const result = await discoverTraefik('http://traefik.local:8080');
+
+			expect(result.services).toHaveLength(0);
+			expect(result.error).toContain('500');
+
+			vi.unstubAllGlobals();
+		});
+
+		it('returns error when fetch throws', async () => {
+			vi.stubGlobal(
+				'fetch',
+				vi.fn(() => Promise.reject(new Error('Network error')))
+			);
+
+			const result = await discoverTraefik('http://traefik.local:8080');
+
+			expect(result.services).toHaveLength(0);
+			expect(result.error).toContain('Network error');
+
+			vi.unstubAllGlobals();
+		});
+	});
+
+	describe('discoverAll', () => {
+		it('marks already-registered services', async () => {
+			mockExec.mockResolvedValue({
+				stdout: JSON.stringify([
+					{
+						Id: 'c1',
+						Names: ['/gitea'],
+						Image: 'gitea/gitea',
+						Ports: [{ IP: '0.0.0.0', PrivatePort: 3000, PublicPort: 3000, Type: 'tcp' }],
+						Labels: {},
+						State: 'running'
+					}
+				])
+			});
+
+			mockFindAllApps.mockResolvedValue([
+				{ id: 'a1', name: 'Gitea', url: 'http://localhost:3000' }
+			]);
+
+			const result = await discoverAll({ dockerSocketPath: '/var/run/docker.sock' });
+
+			expect(result.services).toHaveLength(1);
+			expect(result.services[0].alreadyRegistered).toBe(true);
+		});
+
+		it('deduplicates by URL preferring Traefik', async () => {
+			mockExec.mockResolvedValue({
+				stdout: JSON.stringify([
+					{
+						Id: 'c1',
+						Names: ['/app'],
+						Image: 'app:latest',
+						Ports: [],
+						Labels: {
+							'traefik.http.routers.app.rule': 'Host(`app.example.com`)'
+						},
+						State: 'running'
+					}
+				])
+			});
+
+			vi.stubGlobal(
+				'fetch',
+				vi.fn((url: string) => {
+					if (url.includes('/api/http/routers')) {
+						return Promise.resolve({
+							ok: true,
+							json: () =>
+								Promise.resolve([
+									{
+										name: 'app@docker',
+										rule: 'Host(`app.example.com`)',
+										service: 'app@docker',
+										entryPoints: ['web']
+									}
+								])
+						});
+					}
+					return Promise.resolve({ ok: true, json: () => Promise.resolve([]) });
+				})
+			);
+
+			mockFindAllApps.mockResolvedValue([]);
+
+			const result = await discoverAll({
+				dockerSocketPath: '/var/run/docker.sock',
+				traefikApiUrl: 'http://traefik.local:8080'
+			});
+
+			// Should deduplicate: both Docker (via label) and Traefik discover http://app.example.com
+			const urls = result.services.map((s) => s.url);
+			const unique = new Set(urls);
+			expect(urls.length).toBe(unique.size);
+
+			vi.unstubAllGlobals();
+		});
+
+		it('returns empty when no sources configured', async () => {
+			mockFindAllApps.mockResolvedValue([]);
+
+			const result = await discoverAll({});
+
+			expect(result.services).toHaveLength(0);
+			expect(result.errors).toHaveLength(0);
+		});
+	});
+});
diff --git a/src/lib/server/services/__tests__/exportService.test.ts b/src/lib/server/services/__tests__/exportService.test.ts
new file mode 100644
index 0000000..972ea1f
--- /dev/null
+++ b/src/lib/server/services/__tests__/exportService.test.ts
@@ -0,0 +1,186 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+vi.mock('../../prisma.js', () => ({
+	prisma: {
+		app: { findMany: vi.fn() },
+		board: { findMany: vi.fn() },
+		group: { findMany: vi.fn() },
+		systemSettings: { upsert: vi.fn() }
+	}
+}));
+
+import { prisma } from '../../prisma.js';
+import { exportAllData } from '../exportService.js';
+
+const mockApp = prisma.app as unknown as { findMany: ReturnType<typeof vi.fn> };
+const mockBoard = prisma.board as unknown as { findMany: ReturnType<typeof vi.fn> };
+const mockGroup = prisma.group as unknown as { findMany: ReturnType<typeof vi.fn> };
+const mockSettings = prisma.systemSettings as unknown as {
+	upsert: ReturnType<typeof vi.fn>;
+};
+
+describe('exportService', () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	describe('exportAllData', () => {
+		it('returns export data with version and timestamp', async () => {
+			mockApp.findMany.mockResolvedValue([]);
+			mockBoard.findMany.mockResolvedValue([]);
+			mockGroup.findMany.mockResolvedValue([]);
+			mockSettings.upsert.mockResolvedValue({
+				authMode: 'local',
+				registrationEnabled: true,
+				defaultTheme: 'dark',
+				defaultPrimaryColor: '#6366f1',
+				healthcheckDefaults: '{}'
+			});
+
+			const result = await exportAllData();
+
+			expect(result.version).toBe('1.0');
+			expect(result.exportedAt).toBeTruthy();
+			expect(result.apps).toEqual([]);
+			expect(result.boards).toEqual([]);
+			expect(result.groups).toEqual([]);
+			expect(result.settings).toEqual({
+				authMode: 'local',
+				registrationEnabled: true,
+				defaultTheme: 'dark',
+				defaultPrimaryColor: '#6366f1',
+				healthcheckDefaults: '{}'
+			});
+		});
+
+		it('maps apps to export format stripping internal fields', async () => {
+			mockApp.findMany.mockResolvedValue([
+				{
+					id: 'a1',
+					name: 'Gitea',
+					url: 'https://git.local',
+					icon: 'gitea',
+					iconType: 'simple',
+					description: 'Self-hosted Git',
+					category: 'dev',
+					tags: 'git,code',
+					healthcheckEnabled: true,
+					healthcheckInterval: 300,
+					healthcheckMethod: 'GET',
+					healthcheckExpectedStatus: 200,
+					healthcheckTimeout: 5000,
+					createdById: 'u1',
+					createdAt: new Date(),
+					updatedAt: new Date()
+				}
+			]);
+			mockBoard.findMany.mockResolvedValue([]);
+			mockGroup.findMany.mockResolvedValue([]);
+			mockSettings.upsert.mockResolvedValue({
+				authMode: 'local',
+				registrationEnabled: true,
+				defaultTheme: 'dark',
+				defaultPrimaryColor: '#6366f1',
+				healthcheckDefaults: '{}'
+			});
+
+			const result = await exportAllData();
+
+			expect(result.apps).toHaveLength(1);
+			expect(result.apps[0]).toEqual({
+				name: 'Gitea',
+				url: 'https://git.local',
+				icon: 'gitea',
+				iconType: 'simple',
+				description: 'Self-hosted Git',
+				category: 'dev',
+				tags: 'git,code',
+				healthcheckEnabled: true,
+				healthcheckInterval: 300,
+				healthcheckMethod: 'GET',
+				healthcheckExpectedStatus: 200,
+				healthcheckTimeout: 5000
+			});
+			// Internal fields should not be present
+			expect((result.apps[0] as Record<string, unknown>).id).toBeUndefined();
+			expect((result.apps[0] as Record<string, unknown>).createdById).toBeUndefined();
+		});
+
+		it('maps boards with nested sections and widgets', async () => {
+			mockApp.findMany.mockResolvedValue([]);
+			mockBoard.findMany.mockResolvedValue([
+				{
+					name: 'Dashboard',
+					icon: null,
+					description: 'Main board',
+					isDefault: true,
+					isGuestAccessible: false,
+					backgroundConfig: null,
+					sections: [
+						{
+							title: 'Apps',
+							icon: null,
+							order: 0,
+							isExpandedByDefault: true,
+							widgets: [
+								{
+									type: 'app',
+									order: 0,
+									config: '{}',
+									app: { name: 'Gitea' }
+								}
+							]
+						}
+					]
+				}
+			]);
+			mockGroup.findMany.mockResolvedValue([]);
+			mockSettings.upsert.mockResolvedValue({
+				authMode: 'local',
+				registrationEnabled: true,
+				defaultTheme: 'dark',
+				defaultPrimaryColor: '#6366f1',
+				healthcheckDefaults: '{}'
+			});
+
+			const result = await exportAllData();
+
+			expect(result.boards).toHaveLength(1);
+			expect(result.boards[0].name).toBe('Dashboard');
+			expect(result.boards[0].sections).toHaveLength(1);
+			expect(result.boards[0].sections[0].widgets).toHaveLength(1);
+			expect(result.boards[0].sections[0].widgets[0].appName).toBe('Gitea');
+		});
+
+		it('maps groups stripping internal fields', async () => {
+			mockApp.findMany.mockResolvedValue([]);
+			mockBoard.findMany.mockResolvedValue([]);
+			mockGroup.findMany.mockResolvedValue([
+				{
+					id: 'g1',
+					name: 'Admins',
+					description: 'Admin users',
+					isDefault: false,
+					createdAt: new Date(),
+					updatedAt: new Date()
+				}
+			]);
+			mockSettings.upsert.mockResolvedValue({
+				authMode: 'local',
+				registrationEnabled: true,
+				defaultTheme: 'dark',
+				defaultPrimaryColor: '#6366f1',
+				healthcheckDefaults: '{}'
+			});
+
+			const result = await exportAllData();
+
+			expect(result.groups).toHaveLength(1);
+			expect(result.groups[0]).toEqual({
+				name: 'Admins',
+				description: 'Admin users',
+				isDefault: false
+			});
+		});
+	});
+});
diff --git a/src/lib/server/services/__tests__/importService.test.ts b/src/lib/server/services/__tests__/importService.test.ts
new file mode 100644
index 0000000..a2137f4
--- /dev/null
+++ b/src/lib/server/services/__tests__/importService.test.ts
@@ -0,0 +1,222 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+// Build a transaction mock that mirrors prisma's nested structure
+const txMock = {
+	app: { findFirst: vi.fn(), create: vi.fn(), update: vi.fn() },
+	group: { findUnique: vi.fn(), create: vi.fn(), update: vi.fn() },
+	board: { findFirst: vi.fn(), create: vi.fn(), update: vi.fn() },
+	section: { create: vi.fn(), deleteMany: vi.fn() },
+	widget: { create: vi.fn() },
+	systemSettings: { upsert: vi.fn() }
+};
+
+vi.mock('../../prisma.js', () => ({
+	prisma: {
+		$transaction: vi.fn(async (fn: (tx: typeof txMock) => Promise<void>) => {
+			await fn(txMock);
+		})
+	}
+}));
+
+import { validateImportData, importData } from '../importService.js';
+import type { ExportData } from '../exportService.js';
+
+function buildValidExportData(overrides: Partial<ExportData> = {}): ExportData {
+	return {
+		version: '1.0',
+		exportedAt: new Date().toISOString(),
+		apps: [],
+		boards: [],
+		groups: [],
+		settings: {
+			authMode: 'local',
+			registrationEnabled: true,
+			defaultTheme: 'dark',
+			defaultPrimaryColor: '#6366f1',
+			healthcheckDefaults: '{}'
+		},
+		...overrides
+	};
+}
+
+describe('importService', () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	describe('validateImportData', () => {
+		it('accepts valid export data', () => {
+			const data = buildValidExportData();
+			const result = validateImportData(data);
+			expect(result.success).toBe(true);
+		});
+
+		it('rejects data missing required fields', () => {
+			const result = validateImportData({ version: '1.0' });
+			expect(result.success).toBe(false);
+			if (!result.success) {
+				expect(result.errors.length).toBeGreaterThan(0);
+			}
+		});
+
+		it('rejects non-object input', () => {
+			const result = validateImportData('not an object');
+			expect(result.success).toBe(false);
+		});
+	});
+
+	describe('importData', () => {
+		it('creates new apps when none exist', async () => {
+			const data = buildValidExportData({
+				apps: [
+					{
+						name: 'TestApp',
+						url: 'https://test.local',
+						icon: null,
+						iconType: 'lucide',
+						description: null,
+						category: null,
+						tags: '',
+						healthcheckEnabled: false,
+						healthcheckInterval: 300,
+						healthcheckMethod: 'GET',
+						healthcheckExpectedStatus: 200,
+						healthcheckTimeout: 5000
+					}
+				]
+			});
+
+			txMock.app.findFirst.mockResolvedValue(null);
+			txMock.app.create.mockResolvedValue({ id: 'new-app-id', name: 'TestApp' });
+
+			const result = await importData(data, 'skip');
+
+			expect(result.apps.created).toBe(1);
+			expect(result.apps.skipped).toBe(0);
+			expect(txMock.app.create).toHaveBeenCalledOnce();
+		});
+
+		it('skips existing apps in skip mode', async () => {
+			const data = buildValidExportData({
+				apps: [
+					{
+						name: 'Existing',
+						url: 'https://existing.local',
+						icon: null,
+						iconType: 'lucide',
+						description: null,
+						category: null,
+						tags: '',
+						healthcheckEnabled: false,
+						healthcheckInterval: 300,
+						healthcheckMethod: 'GET',
+						healthcheckExpectedStatus: 200,
+						healthcheckTimeout: 5000
+					}
+				]
+			});
+
+			txMock.app.findFirst.mockResolvedValue({ id: 'existing-id', name: 'Existing' });
+
+			const result = await importData(data, 'skip');
+
+			expect(result.apps.skipped).toBe(1);
+			expect(result.apps.created).toBe(0);
+			expect(txMock.app.update).not.toHaveBeenCalled();
+		});
+
+		it('overwrites existing apps in overwrite mode', async () => {
+			const data = buildValidExportData({
+				apps: [
+					{
+						name: 'Existing',
+						url: 'https://updated.local',
+						icon: null,
+						iconType: 'lucide',
+						description: 'updated',
+						category: null,
+						tags: '',
+						healthcheckEnabled: true,
+						healthcheckInterval: 60,
+						healthcheckMethod: 'GET',
+						healthcheckExpectedStatus: 200,
+						healthcheckTimeout: 5000
+					}
+				]
+			});
+
+			txMock.app.findFirst.mockResolvedValue({ id: 'existing-id', name: 'Existing' });
+
+			const result = await importData(data, 'overwrite');
+
+			expect(result.apps.updated).toBe(1);
+			expect(txMock.app.update).toHaveBeenCalledOnce();
+		});
+
+		it('creates new groups', async () => {
+			const data = buildValidExportData({
+				groups: [{ name: 'NewGroup', description: 'A group', isDefault: false }]
+			});
+
+			txMock.group.findUnique.mockResolvedValue(null);
+
+			const result = await importData(data, 'skip');
+
+			expect(result.groups.created).toBe(1);
+			expect(txMock.group.create).toHaveBeenCalledOnce();
+		});
+
+		it('creates boards with sections and widgets', async () => {
+			const data = buildValidExportData({
+				boards: [
+					{
+						name: 'Board1',
+						icon: null,
+						description: null,
+						isDefault: false,
+						isGuestAccessible: false,
+						backgroundConfig: null,
+						sections: [
+							{
+								title: 'Section1',
+								icon: null,
+								order: 0,
+								isExpandedByDefault: true,
+								widgets: [
+									{ type: 'note', order: 0, config: '{}', appName: null }
+								]
+							}
+						]
+					}
+				]
+			});
+
+			txMock.board.findFirst.mockResolvedValue(null);
+			txMock.board.create.mockResolvedValue({ id: 'board-id' });
+			txMock.section.create.mockResolvedValue({ id: 'section-id' });
+
+			const result = await importData(data, 'skip');
+
+			expect(result.boards.created).toBe(1);
+			expect(txMock.section.create).toHaveBeenCalledOnce();
+			expect(txMock.widget.create).toHaveBeenCalledOnce();
+		});
+
+		it('imports settings when provided', async () => {
+			const data = buildValidExportData({
+				settings: {
+					authMode: 'both',
+					registrationEnabled: false,
+					defaultTheme: 'light',
+					defaultPrimaryColor: '#ff0000',
+					healthcheckDefaults: '{}'
+				}
+			});
+
+			const result = await importData(data, 'skip');
+
+			expect(result.settingsUpdated).toBe(true);
+			expect(txMock.systemSettings.upsert).toHaveBeenCalledOnce();
+		});
+	});
+});
diff --git a/src/lib/utils/__tests__/broadcastSync.test.ts b/src/lib/utils/__tests__/broadcastSync.test.ts
new file mode 100644
index 0000000..237eb65
--- /dev/null
+++ b/src/lib/utils/__tests__/broadcastSync.test.ts
@@ -0,0 +1,137 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+
+// Mock BroadcastChannel in Node environment
+class MockBroadcastChannel {
+	static instances: MockBroadcastChannel[] = [];
+	name: string;
+	onmessage: ((event: { data: unknown }) => void) | null = null;
+	private listeners: Array<{ type: string; handler: (event: { data: unknown }) => void }> = [];
+	closed = false;
+
+	constructor(name: string) {
+		this.name = name;
+		MockBroadcastChannel.instances.push(this);
+	}
+
+	postMessage(data: unknown) {
+		// Broadcast to other instances with same name
+		for (const instance of MockBroadcastChannel.instances) {
+			if (instance !== this && instance.name === this.name && !instance.closed) {
+				for (const listener of instance.listeners) {
+					if (listener.type === 'message') {
+						listener.handler({ data });
+					}
+				}
+			}
+		}
+	}
+
+	addEventListener(type: string, handler: (event: { data: unknown }) => void) {
+		this.listeners.push({ type, handler });
+	}
+
+	removeEventListener(type: string, handler: (event: { data: unknown }) => void) {
+		this.listeners = this.listeners.filter(
+			(l) => !(l.type === type && l.handler === handler)
+		);
+	}
+
+	close() {
+		this.closed = true;
+	}
+
+	static reset() {
+		MockBroadcastChannel.instances = [];
+	}
+}
+
+describe('broadcastSync', () => {
+	beforeEach(() => {
+		MockBroadcastChannel.reset();
+		vi.stubGlobal('window', {});
+		vi.stubGlobal('BroadcastChannel', MockBroadcastChannel);
+	});
+
+	afterEach(() => {
+		vi.unstubAllGlobals();
+		vi.resetModules();
+	});
+
+	it('broadcastThemeChange sends theme-change message', async () => {
+		const { broadcastThemeChange } = await import('$lib/utils/broadcastSync.js');
+
+		const spy = vi.fn();
+		const channel = new MockBroadcastChannel('wal-sync');
+		channel.addEventListener('message', (event: { data: unknown }) => {
+			spy(event.data);
+		});
+
+		broadcastThemeChange({
+			mode: 'dark',
+			primaryHue: 240,
+			primarySaturation: 80,
+			backgroundType: 'none'
+		});
+
+		expect(spy).toHaveBeenCalledWith({
+			type: 'theme-change',
+			payload: {
+				mode: 'dark',
+				primaryHue: 240,
+				primarySaturation: 80,
+				backgroundType: 'none'
+			}
+		});
+	});
+
+	it('broadcastDataChange sends data-change message', async () => {
+		const { broadcastDataChange } = await import('$lib/utils/broadcastSync.js');
+
+		const spy = vi.fn();
+		const channel = new MockBroadcastChannel('wal-sync');
+		channel.addEventListener('message', (event: { data: unknown }) => {
+			spy(event.data);
+		});
+
+		broadcastDataChange('app');
+
+		expect(spy).toHaveBeenCalledWith({
+			type: 'data-change',
+			payload: { entity: 'app' }
+		});
+	});
+
+	it('onSyncMessage registers a listener and returns cleanup', async () => {
+		const { onSyncMessage } = await import('$lib/utils/broadcastSync.js');
+
+		const callback = vi.fn();
+		const cleanup = onSyncMessage(callback);
+
+		// Simulate a message from another tab
+		const sender = new MockBroadcastChannel('wal-sync');
+		sender.postMessage({ type: 'data-change', payload: { entity: 'board' } });
+
+		expect(callback).toHaveBeenCalledWith({
+			type: 'data-change',
+			payload: { entity: 'board' }
+		});
+
+		// Cleanup should work
+		cleanup();
+		expect(typeof cleanup).toBe('function');
+	});
+
+	it('returns no-op cleanup when window is undefined', async () => {
+		vi.stubGlobal('window', undefined);
+		vi.resetModules();
+
+		const { onSyncMessage } = await import('$lib/utils/broadcastSync.js');
+
+		const callback = vi.fn();
+		const cleanup = onSyncMessage(callback);
+
+		expect(typeof cleanup).toBe('function');
+		cleanup(); // Should not throw
+		expect(callback).not.toHaveBeenCalled();
+	});
+});
diff --git a/src/routes/api/apps/quick-add/__tests__/quickAdd.test.ts b/src/routes/api/apps/quick-add/__tests__/quickAdd.test.ts
new file mode 100644
index 0000000..2442251
--- /dev/null
+++ b/src/routes/api/apps/quick-add/__tests__/quickAdd.test.ts
@@ -0,0 +1,152 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+vi.mock('$lib/server/services/appService.js', () => ({
+	create: vi.fn()
+}));
+
+import * as appService from '$lib/server/services/appService.js';
+import { POST } from '../+server.js';
+
+const mockCreate = appService.create as ReturnType<typeof vi.fn>;
+
+function createMockEvent(
+	overrides: {
+		user?: { id: string; role: string } | null;
+		body?: unknown;
+		jsonThrows?: boolean;
+	} = {}
+) {
+	const { user = { id: 'u1', role: 'user' }, body = {}, jsonThrows = false } = overrides;
+
+	return {
+		locals: { user },
+		request: {
+			json: jsonThrows
+				? vi.fn().mockRejectedValue(new Error('Invalid JSON'))
+				: vi.fn().mockResolvedValue(body)
+		}
+	} as unknown as Parameters<typeof POST>[0];
+}
+
+describe('Quick-Add API', () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	describe('POST /api/apps/quick-add', () => {
+		it('creates app with valid URL and name', async () => {
+			const createdApp = {
+				id: 'app1',
+				name: 'My App',
+				url: 'https://myapp.example.com',
+				icon: 'https://myapp.example.com/favicon.ico',
+				iconType: 'url'
+			};
+			mockCreate.mockResolvedValue(createdApp);
+
+			const response = await POST(
+				createMockEvent({
+					body: { url: 'https://myapp.example.com', name: 'My App' }
+				})
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(201);
+			expect(data.success).toBe(true);
+			expect(data.data).toEqual(createdApp);
+			expect(mockCreate).toHaveBeenCalledWith(
+				expect.objectContaining({
+					name: 'My App',
+					url: 'https://myapp.example.com',
+					icon: 'https://myapp.example.com/favicon.ico',
+					iconType: 'url',
+					healthcheckEnabled: true,
+					createdById: 'u1'
+				})
+			);
+		});
+
+		it('derives favicon URL from app URL', async () => {
+			mockCreate.mockResolvedValue({ id: 'app2' });
+
+			await POST(
+				createMockEvent({
+					body: { url: 'https://git.example.com/repos', name: 'Gitea' }
+				})
+			);
+
+			expect(mockCreate).toHaveBeenCalledWith(
+				expect.objectContaining({
+					icon: 'https://git.example.com/favicon.ico'
+				})
+			);
+		});
+
+		it('rejects invalid URL', async () => {
+			const response = await POST(
+				createMockEvent({
+					body: { url: 'not-a-url', name: 'Bad App' }
+				})
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(400);
+			expect(data.success).toBe(false);
+		});
+
+		it('rejects missing name', async () => {
+			const response = await POST(
+				createMockEvent({
+					body: { url: 'https://example.com' }
+				})
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(400);
+			expect(data.success).toBe(false);
+		});
+
+		it('rejects non-http URLs', async () => {
+			const response = await POST(
+				createMockEvent({
+					body: { url: 'ftp://files.example.com', name: 'FTP Server' }
+				})
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(400);
+			expect(data.success).toBe(false);
+		});
+
+		it('returns 400 for invalid JSON body', async () => {
+			const response = await POST(createMockEvent({ jsonThrows: true }));
+			const data = await response.json();
+
+			expect(response.status).toBe(400);
+			expect(data.success).toBe(false);
+		});
+
+		it('returns 500 when service throws', async () => {
+			mockCreate.mockRejectedValue(new Error('DB error'));
+
+			const response = await POST(
+				createMockEvent({
+					body: { url: 'https://example.com', name: 'Failing App' }
+				})
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(500);
+			expect(data.success).toBe(false);
+		});
+
+		it('redirects when not authenticated', async () => {
+			try {
+				await POST(createMockEvent({ user: null }));
+				expect.unreachable('Should have thrown redirect');
+			} catch (e) {
+				expect(e).toBeDefined();
+			}
+		});
+	});
+});
diff --git a/src/routes/api/users/me/preferences/__tests__/preferences.test.ts b/src/routes/api/users/me/preferences/__tests__/preferences.test.ts
new file mode 100644
index 0000000..a436a43
--- /dev/null
+++ b/src/routes/api/users/me/preferences/__tests__/preferences.test.ts
@@ -0,0 +1,191 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+vi.mock('$lib/server/prisma.js', () => ({
+	prisma: {
+		user: {
+			findUnique: vi.fn(),
+			update: vi.fn()
+		}
+	}
+}));
+
+import { prisma } from '$lib/server/prisma.js';
+import { GET, PATCH } from '../+server.js';
+
+const mockUser = prisma.user as unknown as {
+	findUnique: ReturnType<typeof vi.fn>;
+	update: ReturnType<typeof vi.fn>;
+};
+
+function createMockEvent(
+	overrides: {
+		user?: { id: string; role: string } | null;
+		body?: unknown;
+	} = {}
+) {
+	const { user = { id: 'u1', role: 'user' }, body = {} } = overrides;
+
+	return {
+		locals: { user },
+		request: {
+			json: vi.fn().mockResolvedValue(body)
+		}
+	} as unknown as Parameters<typeof GET>[0];
+}
+
+describe('User Preferences API', () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+	});
+
+	describe('GET /api/users/me/preferences', () => {
+		it('returns preferences for authenticated user', async () => {
+			const prefs = {
+				themeMode: 'dark',
+				primaryHue: 240,
+				primarySaturation: 80,
+				backgroundType: 'none',
+				locale: 'en'
+			};
+			mockUser.findUnique.mockResolvedValue(prefs);
+
+			const response = await GET(createMockEvent());
+			const data = await response.json();
+
+			expect(response.status).toBe(200);
+			expect(data.success).toBe(true);
+			expect(data.data).toEqual(prefs);
+		});
+
+		it('returns 404 when user not found', async () => {
+			mockUser.findUnique.mockResolvedValue(null);
+
+			const response = await GET(createMockEvent());
+			const data = await response.json();
+
+			expect(response.status).toBe(404);
+			expect(data.success).toBe(false);
+		});
+
+		it('redirects when not authenticated', async () => {
+			try {
+				await GET(createMockEvent({ user: null }));
+				expect.unreachable('Should have thrown redirect');
+			} catch (e) {
+				// SvelteKit redirect is thrown as an object with status and location
+				expect(e).toBeDefined();
+			}
+		});
+	});
+
+	describe('PATCH /api/users/me/preferences', () => {
+		it('updates theme preferences', async () => {
+			const updatedPrefs = {
+				themeMode: 'light',
+				primaryHue: 120,
+				primarySaturation: 60,
+				backgroundType: 'mesh',
+				locale: 'ru'
+			};
+			mockUser.update.mockResolvedValue(updatedPrefs);
+
+			const response = await PATCH(
+				createMockEvent({
+					body: {
+						themeMode: 'light',
+						primaryHue: 120,
+						primarySaturation: 60,
+						backgroundType: 'mesh',
+						locale: 'ru'
+					}
+				})
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(200);
+			expect(data.success).toBe(true);
+			expect(data.data).toEqual(updatedPrefs);
+		});
+
+		it('rejects invalid themeMode', async () => {
+			const response = await PATCH(
+				createMockEvent({ body: { themeMode: 'invalid' } })
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(400);
+			expect(data.success).toBe(false);
+			expect(data.error).toContain('themeMode');
+		});
+
+		it('rejects primaryHue out of range', async () => {
+			const response = await PATCH(
+				createMockEvent({ body: { primaryHue: 500 } })
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(400);
+			expect(data.success).toBe(false);
+		});
+
+		it('rejects primarySaturation out of range', async () => {
+			const response = await PATCH(
+				createMockEvent({ body: { primarySaturation: -10 } })
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(400);
+			expect(data.success).toBe(false);
+		});
+
+		it('rejects invalid backgroundType', async () => {
+			const response = await PATCH(
+				createMockEvent({ body: { backgroundType: 'invalid' } })
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(400);
+			expect(data.success).toBe(false);
+		});
+
+		it('rejects invalid locale', async () => {
+			const response = await PATCH(
+				createMockEvent({ body: { locale: 'fr' } })
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(400);
+			expect(data.success).toBe(false);
+		});
+
+		it('rejects request with no valid fields', async () => {
+			const response = await PATCH(
+				createMockEvent({ body: { unknownField: 'value' } })
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(400);
+			expect(data.success).toBe(false);
+		});
+
+		it('allows null values to reset preferences', async () => {
+			mockUser.update.mockResolvedValue({
+				themeMode: null,
+				primaryHue: null,
+				primarySaturation: null,
+				backgroundType: null,
+				locale: null
+			});
+
+			const response = await PATCH(
+				createMockEvent({
+					body: { themeMode: null, primaryHue: null }
+				})
+			);
+			const data = await response.json();
+
+			expect(response.status).toBe(200);
+			expect(data.success).toBe(true);
+		});
+	});
+});