Add targeted Vitest coverage

tests/db.index.spec.ts

@@ -0,0 +1,66 @@
+import { describe, expect, test, vi, beforeEach } from 'vitest';
+
+const makeDexieMock = () => {
+  const version = vi.fn().mockReturnThis();
+  const stores = vi.fn().mockReturnThis();
+  const upgrade = vi.fn().mockReturnThis();
+  const table = vi.fn().mockReturnValue({
+    count: vi.fn().mockResolvedValue(0),
+    toArray: vi.fn().mockResolvedValue([]),
+    bulkAdd: vi.fn(),
+  });
+
+  class MockDexie {
+    version = version;
+    stores = stores;
+    upgrade = upgrade;
+    table = table;
+    constructor() {}
+  }
+
+  return { MockDexie, version };
+};
+
+describe('db/index initializeDatabase', () => {
+  beforeEach(() => {
+    vi.resetModules();
+    vi.clearAllMocks();
+  });
+
+  test('initializeDatabase calls applyMigrations with db', async () => {
+    const { MockDexie } = makeDexieMock();
+    const applyMigrations = vi.fn().mockResolvedValue(undefined);
+
+    vi.mock('dexie', () => ({ default: MockDexie, Dexie: MockDexie, Table: class {} }));
+    vi.mock('../src/db/migrations', () => ({ applyMigrations }));
+
+    const { initializeDatabase, db } = await import('../src/db');
+    await initializeDatabase();
+
+    expect(applyMigrations).toHaveBeenCalledWith(db);
+  });
+
+  test('initializeDatabase rejects when applyMigrations fails', async () => {
+    const { MockDexie } = makeDexieMock();
+    const applyMigrations = vi.fn().mockRejectedValue(new Error('fail'));
+
+    vi.mock('dexie', () => ({ default: MockDexie, Dexie: MockDexie, Table: class {} }));
+    vi.mock('../src/db/migrations', () => ({ applyMigrations }));
+
+    const { initializeDatabase } = await import('../src/db');
+
+    await expect(initializeDatabase()).rejects.toThrow('fail');
+  });
+
+  test('StockFillDB sets up versions on construction', async () => {
+    const { MockDexie, version } = makeDexieMock();
+    vi.mock('dexie', () => ({ default: MockDexie, Dexie: MockDexie, Table: class {} }));
+    vi.mock('../src/db/migrations', () => ({ applyMigrations: vi.fn() }));
+
+    const { db } = await import('../src/db');
+
+    expect(version).toHaveBeenCalled();
+    expect((version as any).mock.calls.length).toBeGreaterThanOrEqual(1);
+    expect(db).toBeDefined();
+  });
+});