Render startup immediately and defer native work with a smooth home transition

mobile/test/widgets/tp_startup_test.dart

@@ -3,9 +3,10 @@ import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:hepan_everyday/app/tp_startup.dart';
+import 'package:hepan_everyday/app/tp_launch_page.dart';
 
 void main() {
-  testWidgets('waiting initialization does not replace the native launch', (
+  testWidgets('waiting initialization keeps painted brand frames', (
     tester,
   ) async {
     await tester.pumpWidget(const SizedBox());
@@ -16,13 +17,14 @@ void main() {
       child: const MaterialApp(home: Text('已准备好课表')),
     ).then((_) => startupFinished = true);
     await tester.pump();
-    expect(startupFinished, isFalse);
+    expect(startupFinished, isTrue);
+    expect(find.byType(TpLaunchPage), findsOneWidget);
     expect(tester.binding.sendFramesToEngine, isTrue);
     expect(find.text('TPSchedule'), findsNothing);
     expect(find.text('已准备好课表'), findsNothing);
     ready.complete();
     await startup;
-    await tester.pump();
+    await tester.pumpAndSettle();
     expect(find.text('已准备好课表'), findsOneWidget);
     expect(find.text('TPSchedule'), findsNothing);
     expect(tester.binding.sendFramesToEngine, isTrue);
@@ -37,7 +39,7 @@ void main() {
       ready: ready,
       child: const MaterialApp(home: Text('保存的课表')),
     );
-    await tester.pump();
+    await tester.pumpAndSettle();
     expect(find.text('保存的课表'), findsOneWidget);
     expect(find.text('TPSchedule'), findsNothing);
     tester.binding.handleAppLifecycleStateChanged(AppLifecycleState.paused);
@@ -57,7 +59,7 @@ void main() {
       );
       ready.completeError(StateError('storage failed'));
       await startup;
-      await tester.pump();
+      await tester.pumpAndSettle();
       expect(find.text('恢复保存文件'), findsOneWidget);
       expect(tester.binding.sendFramesToEngine, isTrue);
       expect(tester.takeException(), isNull);