tests: Add tests for storageInit()

Ensures that default settings are being merged with the existing
extension settings found in the browser as appropriate.

tests/lib/storageInit.test.ts

@@ -0,0 +1,47 @@
+import { describe, expect, it, vi } from 'vitest'
+import { storageInit } from '@/lib/storageInit'
+import type { StorageAll } from '@/types/StorageAll'
+
+const browserMock = {
+  storage: {
+    sync: {
+      get: vi.fn(async (_: string | string[] | Record<string, any> | null | undefined): Promise<Record<string, any>> => ({ blockDefault: true })),
+      set: vi.fn(async (_: Record<string, any>): Promise<void> => {})
+    },
+
+    local: {
+      get: vi.fn(async (_: string | string[] | Record<string, any> | null | undefined): Promise<Record<string, any>> => ({})),
+      set: vi.fn(async (_: Record<string, any>): Promise<void> => {})
+    }
+  }
+}
+
+vi.stubGlobal('browser', browserMock)
+
+const defaultStorage: StorageAll = {
+  sync: {
+    provider: 'mullvad',
+    blockDefault: false
+  },
+
+  local: {
+    servers: [],
+    lastUpdated: 0
+  }
+}
+
+describe('storageInit()', () => {
+  it('should initialize with default values with existing browser storage values taking priority', async () => {
+    expect(await storageInit(defaultStorage)).toEqual({
+      sync: {
+        provider: 'mullvad',
+        blockDefault: true
+      },
+
+      local: {
+        servers: [],
+        lastUpdated: 0
+      }
+    })
+  })
+})