48 lines
1.5 KiB
Dart
48 lines
1.5 KiB
Dart
import 'package:flutter/material.dart';
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import 'package:flutter_test/flutter_test.dart';
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import 'package:miler/widget/Bottom_page.dart';
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/// The shell keeps every tab alive in an `IndexedStack`: all four pages are
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/// built at launch and switching tabs only changes which one is painted. So a
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/// page that loads in `initState` shows whatever was true before the rider did
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/// anything — which is exactly how a completed stop failed to appear on
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/// Activity. Pages re-read when their index comes forward, so the notifier that
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/// tells them has to actually change.
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void main() {
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testWidgets('an IndexedStack builds every child up front', (tester) async {
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final built = <int>[];
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Widget page(int i) => Builder(builder: (_) {
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built.add(i);
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return SizedBox(key: ValueKey('page$i'));
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});
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await tester.pumpWidget(
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MaterialApp(
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home: IndexedStack(index: 0, children: [page(0), page(1), page(2)]),
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),
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);
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expect(
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built,
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containsAll(<int>[0, 1, 2]),
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reason: 'this is why initState cannot be a page\'s only load',
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);
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});
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test('the shell publishes the tab on screen', () {
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// Starts on Home and is a broadcast point a page can listen to.
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var heard = <int>[];
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void listener() => heard.add(BottomPage.currentTab.value);
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BottomPage.currentTab.addListener(listener);
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addTearDown(() => BottomPage.currentTab.removeListener(listener));
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BottomPage.currentTab.value = 2;
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BottomPage.currentTab.value = 1;
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expect(heard, [2, 1]);
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});
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}
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