From e5b0767a439cb9c40c59b4ca36cd74ce2f4f8aa2 Mon Sep 17 00:00:00 2001
From: Danila Poyarkov <dev@dannote.net>
Date: Tue, 5 May 2026 21:58:12 +0300
Subject: [PATCH] test(app): cover Tauri font cache helpers

---
 tests/engine/tauri-font-cache.test.ts | 80 +++++++++++++++++++++++++++
 tests/helpers/tauri-mocks.ts          | 19 +++++++
 2 files changed, 99 insertions(+)
 create mode 100644 tests/engine/tauri-font-cache.test.ts
 create mode 100644 tests/helpers/tauri-mocks.ts

diff --git a/tests/engine/tauri-font-cache.test.ts b/tests/engine/tauri-font-cache.test.ts
new file mode 100644
index 000000000..9a27aeb52
--- /dev/null
+++ b/tests/engine/tauri-font-cache.test.ts
@@ -0,0 +1,80 @@
+import { afterEach, describe, expect, test } from 'bun:test'
+
+import { clearDownloadedFontCache, downloadedFontCacheSummary } from '@/app/editor/fonts/cache'
+import { clearTauriMocks, mockTauriIPC } from '../helpers/tauri-mocks'
+
+const encoder = new TextEncoder()
+
+afterEach(async () => {
+  await clearTauriMocks()
+})
+
+describe('Tauri downloaded font cache helpers', () => {
+  test('summarizes manifest entries through mocked plugin-fs IPC', async () => {
+    await mockTauriIPC((cmd, args) => {
+      expect(cmd).toBe('plugin:fs|read_file')
+      expect(args).toMatchObject({ path: 'font-cache/v1/manifest.json' })
+      return [...encoder.encode(JSON.stringify({
+        version: 1,
+        entries: {
+          one: {
+            family: 'Noto Sans SC',
+            style: 'Regular',
+            file: 'one.ttf',
+            byteLength: 10,
+            sha256: 'a',
+            updatedAt: 100
+          },
+          two: {
+            family: 'Noto Naskh Arabic',
+            style: 'Regular',
+            file: 'two.ttf',
+            byteLength: 25,
+            sha256: 'b',
+            updatedAt: 250
+          }
+        }
+      }))]
+    })
+
+    await expect(downloadedFontCacheSummary()).resolves.toEqual({
+      count: 2,
+      byteLength: 35,
+      updatedAt: 250
+    })
+  })
+
+  test('returns an empty summary when manifest is missing', async () => {
+    await mockTauriIPC((cmd) => {
+      expect(cmd).toBe('plugin:fs|read_file')
+      throw new Error('missing')
+    })
+
+    await expect(downloadedFontCacheSummary()).resolves.toEqual({
+      count: 0,
+      byteLength: 0,
+      updatedAt: null
+    })
+  })
+
+  test('clears the cache directory through mocked plugin-fs IPC', async () => {
+    const calls: Array<{ cmd: string; args: unknown }> = []
+    await mockTauriIPC((cmd, args) => {
+      calls.push({ cmd, args })
+      return null
+    })
+
+    await clearDownloadedFontCache()
+
+    const { BaseDirectory } = await import('@tauri-apps/plugin-fs')
+    expect(calls).toEqual([
+      {
+        cmd: 'plugin:fs|remove',
+        args: {
+          path: 'font-cache/v1',
+          options: { baseDir: BaseDirectory.AppLocalData, recursive: true }
+        }
+      }
+    ])
+  })
+})
diff --git a/tests/helpers/tauri-mocks.ts b/tests/helpers/tauri-mocks.ts
new file mode 100644
index 000000000..c14005c7f
--- /dev/null
+++ b/tests/helpers/tauri-mocks.ts
@@ -0,0 +1,19 @@
+export function installTauriMockWindow() {
+  const windowLike = globalThis as typeof globalThis & {
+    __TAURI_INTERNALS__?: unknown
+    __TAURI_EVENT_PLUGIN_INTERNALS__?: unknown
+  }
+  Object.assign(globalThis, { window: windowLike })
+}
+
+export async function mockTauriIPC(handler: (cmd: string, args: unknown) => unknown) {
+  installTauriMockWindow()
+  const { mockIPC } = await import('@tauri-apps/api/mocks')
+  mockIPC(handler)
+}
+
+export async function clearTauriMocks() {
+  if (!('window' in globalThis)) return
+  const { clearMocks } = await import('@tauri-apps/api/mocks')
+  clearMocks()
+}