test: expand honest whole-repo coverage

Adds broad coverage across stores, hooks, and runtime utilities while switching `vitest.config.ts` to an explicit whole-repo include list. This turns the coverage report into a real repo-wide baseline instead of an imported-file subset.

src/lib/__tests__/init-translations.test.ts

@@ -0,0 +1,59 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const testState = vi.hoisted(() => {
+  const i18next = {
+    init: vi.fn(),
+    use: vi.fn(),
+  };
+  i18next.use.mockImplementation(() => i18next);
+
+  return {
+    backendPlugin: { name: 'backend-plugin' },
+    detectorPlugin: { name: 'detector-plugin' },
+    i18next,
+    reactPlugin: { name: 'react-plugin' },
+  };
+});
+
+vi.mock('i18next', () => ({
+  default: testState.i18next,
+}));
+
+vi.mock('i18next-http-backend', () => ({
+  default: testState.backendPlugin,
+}));
+
+vi.mock('i18next-browser-languagedetector', () => ({
+  default: testState.detectorPlugin,
+}));
+
+vi.mock('react-i18next', () => ({
+  initReactI18next: testState.reactPlugin,
+}));
+
+describe('init-translations', () => {
+  beforeEach(() => {
+    vi.resetModules();
+    testState.i18next.use.mockClear();
+    testState.i18next.init.mockClear();
+    testState.i18next.use.mockImplementation(() => testState.i18next);
+  });
+
+  it('initializes i18next with the backend, detector, react plugin, and supported languages', async () => {
+    await import('../init-translations');
+
+    expect(testState.i18next.use).toHaveBeenNthCalledWith(1, testState.backendPlugin);
+    expect(testState.i18next.use).toHaveBeenNthCalledWith(2, testState.detectorPlugin);
+    expect(testState.i18next.use).toHaveBeenNthCalledWith(3, testState.reactPlugin);
+    expect(testState.i18next.init).toHaveBeenCalledWith(
+      expect.objectContaining({
+        fallbackLng: 'en',
+        ns: ['default'],
+        defaultNS: 'default',
+        backend: { loadPath: './translations/{{lng}}/{{ns}}.json' },
+      }),
+    );
+    expect(testState.i18next.init.mock.calls[0]?.[0]?.supportedLngs).toContain('en');
+    expect(testState.i18next.init.mock.calls[0]?.[0]?.supportedLngs).toContain('ja');
+  });
+});

src/lib/__tests__/snow.test.ts

@@ -0,0 +1,47 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+describe('snow', () => {
+  beforeEach(() => {
+    document.head.innerHTML = '';
+    document.body.innerHTML = '';
+    vi.restoreAllMocks();
+    vi.useRealTimers();
+    vi.resetModules();
+  });
+
+  it('creates and removes a deterministic snow field', async () => {
+    const mathRandomSpy = vi.spyOn(Math, 'random').mockReturnValue(0.5);
+    const { initSnow, removeSnow } = await import('../snow');
+
+    initSnow({ flakeCount: 3 });
+
+    const snowfield = document.getElementById('js-snowfield');
+    expect(snowfield).toBeTruthy();
+    expect(snowfield?.children).toHaveLength(2);
+    expect(document.head.querySelector('style')?.textContent).toContain('fall-1');
+
+    removeSnow();
+    expect(document.getElementById('js-snowfield')).toBeNull();
+
+    mathRandomSpy.mockRestore();
+  });
+
+  it('prefers the special theme store and otherwise falls back to christmas dates', async () => {
+    const useSpecialThemeStore = (await import('../../stores/use-special-theme-store')).default;
+    const { shouldShowSnow } = await import('../snow');
+
+    useSpecialThemeStore.setState({ isEnabled: true });
+    expect(shouldShowSnow()).toBe(true);
+
+    useSpecialThemeStore.setState({ isEnabled: false });
+    expect(shouldShowSnow()).toBe(false);
+
+    useSpecialThemeStore.setState({ isEnabled: null });
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date('2024-12-24T00:00:00Z'));
+    expect(shouldShowSnow()).toBe(true);
+
+    vi.setSystemTime(new Date('2024-07-04T00:00:00Z'));
+    expect(shouldShowSnow()).toBe(false);
+  });
+});

src/lib/__tests__/update-favicon.test.ts

@@ -0,0 +1,67 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+describe('update-favicon', () => {
+  beforeEach(() => {
+    document.head.innerHTML = '';
+    document.body.innerHTML = '';
+    vi.resetModules();
+  });
+
+  it('creates a favicon link and replaces it only when the target icon changes', async () => {
+    const { updateFavicon } = await import('../update-favicon');
+
+    updateFavicon(false);
+    expect(document.querySelectorAll('link[rel="icon"]')).toHaveLength(1);
+    expect(document.querySelector('link[rel="icon"]')?.getAttribute('href')).toBe('/favicon.ico');
+
+    updateFavicon(false);
+    expect(document.querySelectorAll('link[rel="icon"]')).toHaveLength(1);
+
+    updateFavicon(true);
+    expect(document.querySelectorAll('link[rel="icon"]')).toHaveLength(1);
+    expect(document.querySelector('link[rel="icon"]')?.getAttribute('href')).toBe('/favicon2.ico');
+  });
+
+  it('marks only non-special, non-routing aggregate sfw boards as sfw', async () => {
+    const { isSfwBoard } = await import('../update-favicon');
+
+    expect(
+      isSfwBoard({
+        pathname: '/',
+        isSpecialTheme: false,
+        isInAllView: false,
+        isInSubscriptionsView: false,
+        isInModView: false,
+        subplebbitAddress: 'music.eth',
+        directories: [{ address: 'music.eth', nsfw: false }],
+      }),
+    ).toBe(false);
+
+    expect(
+      isSfwBoard({
+        pathname: '/music.eth',
+        isSpecialTheme: false,
+        isInAllView: false,
+        isInSubscriptionsView: false,
+        isInModView: false,
+        subplebbitAddress: 'music.eth',
+        directories: [
+          { address: 'music.eth', nsfw: false },
+          { address: 'flash.eth', nsfw: true },
+        ],
+      }),
+    ).toBe(true);
+
+    expect(
+      isSfwBoard({
+        pathname: '/flash.eth',
+        isSpecialTheme: false,
+        isInAllView: false,
+        isInSubscriptionsView: false,
+        isInModView: false,
+        subplebbitAddress: 'flash.eth',
+        directories: [{ address: 'flash.eth', nsfw: true }],
+      }),
+    ).toBe(false);
+  });
+});