Added required code coverage for jest

src/app/App.tsx

@@ -0,0 +1,63 @@
+import { useEffect, FC } from 'react';
+import { Route, Switch } from 'react-router-dom';
+import NotFound from '../common/NotFound';
+import { ServersMap } from '../servers/data';
+import { Settings } from '../settings/reducers/settings';
+import { changeThemeInMarkup } from '../utils/theme';
+import { AppUpdateBanner } from '../common/AppUpdateBanner';
+import { forceUpdate } from '../utils/helpers/sw';
+import './App.scss';
+
+interface AppProps {
+  fetchServers: () => void;
+  servers: ServersMap;
+  settings: Settings;
+  resetAppUpdate: () => void;
+  appUpdated: boolean;
+}
+
+const App = (
+  MainHeader: FC,
+  Home: FC,
+  MenuLayout: FC,
+  CreateServer: FC,
+  EditServer: FC,
+  Settings: FC,
+  ShlinkVersionsContainer: FC,
+) => ({ fetchServers, servers, settings, appUpdated, resetAppUpdate }: AppProps) => {
+  useEffect(() => {
+    // On first load, try to fetch the remote servers if the list is empty
+    if (Object.keys(servers).length === 0) {
+      fetchServers();
+    }
+
+    changeThemeInMarkup(settings.ui?.theme ?? 'light');
+  }, []);
+
+  return (
+    <div className="container-fluid app-container">
+      <MainHeader />
+
+      <div className="app">
+        <div className="shlink-wrapper">
+          <Switch>
+            <Route exact path="/" component={Home} />
+            <Route exact path="/settings" component={Settings} />
+            <Route exact path="/server/create" component={CreateServer} />
+            <Route exact path="/server/:serverId/edit" component={EditServer} />
+            <Route path="/server/:serverId" component={MenuLayout} />
+            <Route component={NotFound} />
+          </Switch>
+        </div>
+
+        <div className="shlink-footer">
+          <ShlinkVersionsContainer />
+        </div>
+      </div>
+
+      <AppUpdateBanner isOpen={appUpdated} toggle={resetAppUpdate} forceUpdate={forceUpdate} />
+    </div>
+  );
+};
+
+export default App;