fix(test): use constructor injection for key material in tests

Replace navigator mocking with constructor parameter for key derivation.
This avoids environment-specific issues with jsdom's navigator object
in CI while maintaining the same encryption/decryption behavior.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: msujaws

src/lib/storage/api-key-storage.test.ts

@@ -4,7 +4,7 @@ import { ApiKeyStorage } from './api-key-storage'
 describe('ApiKeyStorage', () => {
   let storage: ApiKeyStorage
   let localStorageMock: Record<string, string>
-  const mockUserAgent = 'Mozilla/5.0 (Test) TestBrowser/1.0'
+  const testKeyMaterial = 'test-key-material-for-encryption'
 
   beforeEach(() => {
     // Mock localStorage
@@ -27,19 +27,8 @@ describe('ApiKeyStorage', () => {
       key: vi.fn(),
     })
 
-    // Mock navigator.userAgent for consistent encryption key derivation
-    // Use Object.create to preserve the navigator prototype chain for jsdom in CI
-    const navigatorMock = Object.create(
-      Object.getPrototypeOf(globalThis.navigator),
-      Object.getOwnPropertyDescriptors(globalThis.navigator),
-    )
-    Object.defineProperty(navigatorMock, 'userAgent', {
-      value: mockUserAgent,
-      configurable: true,
-    })
-    vi.stubGlobal('navigator', navigatorMock)
-
-    storage = new ApiKeyStorage()
+    // Use constructor parameter for consistent key derivation in tests
+    storage = new ApiKeyStorage(testKeyMaterial)
   })
 
   afterEach(() => {

src/lib/storage/api-key-storage.ts

@@ -13,15 +13,24 @@ interface EncryptedData {
 export class ApiKeyStorage {
   private encoder = new TextEncoder()
   private decoder = new TextDecoder()
+  private keyMaterialOverride?: string
+
+  /**
+   * @param keyMaterialOverride - Optional override for key derivation (for testing only)
+   */
+  constructor(keyMaterialOverride?: string) {
+    this.keyMaterialOverride = keyMaterialOverride
+  }
 
   /**
    * Derive a crypto key from the user agent string
    * This provides basic obfuscation (not cryptographically secure against determined attackers)
    * but protects against casual inspection of localStorage
    */
   private async deriveCryptoKey(): Promise<CryptoKey> {
-    // Use user agent as key material (stable across sessions)
-    const keyMaterial = this.encoder.encode(navigator.userAgent + 'bugzilla-kanban-salt')
+    // Use user agent as key material (stable across sessions), or override for testing
+    const keySource = this.keyMaterialOverride ?? navigator.userAgent
+    const keyMaterial = this.encoder.encode(keySource + 'bugzilla-kanban-salt')
 
     // Import as raw key material
     const importedKey = await crypto.subtle.importKey(