test: proper sanity check; exclude WasmTest from coverage (#8)

src/__tests__/sanity-check.test.tsx

@@ -1,6 +1,10 @@
-import { render, screen } from '@testing-library/react';
+import App from '~/App';
+import { renderWithProviders, screen } from '~/test-utils/test-helper';
 
-test('hello', () => {
-  render(<div>hello</div>);
-  expect(screen.getByText('hello')).toBeInTheDocument();
+test('should be able to render App', () => {
+  renderWithProviders(<App />);
+
+  // Quick sanity check of known strings.
+  expect(screen.getByText(/仅在浏览器内对文件进行解锁/i)).toBeInTheDocument();
+  expect(screen.getByText(/UnlockMusic 团队/i)).toBeInTheDocument();
 });