use jest-test/vitest

package.json

@@ -55,6 +55,7 @@
     "signal-polyfill": "^0.1.0"
   },
   "devDependencies": {
+    "@testing-library/jest-dom": "^6.4.2",
     "@testing-library/react": "^15.0.2",
     "@testing-library/user-event": "^14.5.2",
     "@types/node": "^20.12.7",

tests/03_component.spec.tsx

@@ -1,9 +1,11 @@
-import { test } from 'vitest';
-import { render, screen } from '@testing-library/react';
+import { afterEach, expect, test } from 'vitest';
+import { cleanup, render, screen } from '@testing-library/react';
 import { userEvent } from '@testing-library/user-event';
 
 import { Signal, useSignal } from 'use-signals';
 
+afterEach(cleanup);
+
 test('counter app', async () => {
   const user = userEvent.setup();
   const counter = new Signal.State(0);
@@ -12,17 +14,17 @@ test('counter app', async () => {
     const inc = () => counter.set(counter.get() + 1);
     return (
       <>
-        <div>Count: {count}</div>
+        <div data-testid="count">{count}</div>
         <button type="button" onClick={inc}>
           +1
         </button>
       </>
     );
   };
   render(<App />);
-  await screen.findByText('Count: 0');
+  expect(screen.getByTestId('count')).toHaveTextContent('0');
   await user.click(screen.getByRole('button'));
-  await screen.findByText('Count: 1');
+  expect(screen.getByTestId('count')).toHaveTextContent('1');
   await user.click(screen.getByRole('button'));
-  await screen.findByText('Count: 2');
+  expect(screen.getByTestId('count')).toHaveTextContent('2');
 });

tests/vitest-setup.js

@@ -0,0 +1 @@
+import '@testing-library/jest-dom/vitest';

tsconfig.json

@@ -5,6 +5,7 @@
     "downlevelIteration": true,
     "esModuleInterop": true,
     "module": "nodenext",
+    "skipLibCheck": true,
     "allowJs": true,
     "verbatimModuleSyntax": true,
     "noUncheckedIndexedAccess": true,

vite.config.ts

@@ -11,7 +11,10 @@ export default defineConfig(({ mode }) => {
   if (mode === 'test') {
     return {
       resolve: { alias: { 'use-signals': resolve('src') } },
-      test: { environment: 'jsdom' },
+      test: {
+        environment: 'jsdom',
+        setupFiles: ['./tests/vitest-setup.js'],
+      },
     };
   }
   if (!DIR) {