test: add test case for plugin bootstrap (#3529)

apps/core/src/_plugin/index.test.tsx

@@ -0,0 +1,42 @@
+import { assertExists } from '@blocksuite/global/utils';
+import {
+  registeredPluginAtom,
+  rootStore,
+} from '@toeverything/plugin-infra/atom';
+import { use } from 'foxact/use';
+import { useAtomValue } from 'jotai';
+import { Provider } from 'jotai/react';
+import { StrictMode } from 'react';
+import { createRoot } from 'react-dom/client';
+
+import { _pluginNestedImportsMap } from '../bootstrap/plugins/setup';
+import { pluginRegisterPromise } from '../bootstrap/register-plugins';
+
+const root = document.getElementById('app');
+assertExists(root);
+
+const App = () => {
+  use(pluginRegisterPromise);
+  const plugins = useAtomValue(registeredPluginAtom);
+  _pluginNestedImportsMap.forEach(value => {
+    const exports = value.get('index.js');
+    assertExists(exports);
+    assertExists(exports?.get('entry'));
+  });
+  return (
+    <div>
+      <div data-plugins-load-status="success">Successfully loaded plugins:</div>
+      {plugins.map(plugin => {
+        return <div key={plugin}>{plugin}</div>;
+      })}
+    </div>
+  );
+};
+
+createRoot(root).render(
+  <StrictMode>
+    <Provider store={rootStore}>
+      <App />
+    </Provider>
+  </StrictMode>
+);