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

src/App.tsx

@@ -15,7 +15,7 @@ function App() {
         <Box mt="8">
           <FileListing />
         </Box>
-        {localStorage.__dev_test === '1' && <WasmTest />}
+        <WasmTest />
         <Footer />
       </Container>
     </Box>

src/WasmTest.tsx

@@ -1,5 +1,6 @@
 import { loadLibParakeet, BlobSink, createArrayBufferReader } from '@jixun/libparakeet';
 
+/* c8 ignore start: test only code */
 function testWasm() {
   loadLibParakeet().then(async (mod) => {
     const data = new Uint8Array(0x2000);
@@ -23,9 +24,15 @@ function testWasm() {
 }
 
 export function WasmTest() {
+  // Some secret test flags...
+  if (localStorage.__dev_test !== '1') {
+    return null;
+  }
+
   return (
     <button onClick={testWasm} type="button">
       Test WASM
     </button>
   );
 }
+/* c8 ignore stop: test only code */

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();
 });