feat: drive the reader with a D-pad

app/test/app_widget_test.dart

@@ -927,6 +927,184 @@ void main() {
     debugDefaultTargetPlatformOverride = null;
   });
 
+  group('a D-pad drives the reader on a touch host', () {
+    late AppDependencies stubDeps;
+
+    setUp(() {
+      stubDeps = AppDependencies(
+        database: MewsDatabase.test(NativeDatabase.memory()),
+        fetch: FakeFetch({
+          'https://example.com/a.html': _page(
+              'Page A',
+              '<h1>Page A</h1><p><a href="b.html">To page B</a></p>'
+                  '<p><a href="c.html">To page C</a></p>'
+                  '<form action="/sign" method="post">'
+                  '<input type="text" name="name" />'
+                  '<input type="submit" value="Sign" /></form>'
+                  '${'<p>Padding paragraph to make the page scroll.</p>' * 60}'
+                  '<p><a href="c.html">Far down to page C</a></p>'),
+          'https://example.com/b.html':
+              _page('Page B', '<h1>Page B</h1><p>The second pages content.</p>'),
+          'https://example.com/c.html':
+              _page('Page C', '<h1>Page C</h1><p>The third pages content.</p>'),
+        }),
+        strings: strings,
+      );
+    });
+
+    tearDown(() => stubDeps.db.close());
+
+    Future<void> openA(WidgetTester tester) async {
+      debugDefaultTargetPlatformOverride = TargetPlatform.android;
+      await tester.pumpWidget(MewsApp(deps: stubDeps, strings: strings));
+      await tester.pumpAndSettle();
+      await stubDeps.browser.open('https://example.com/a.html');
+      await tester.pumpAndSettle();
+    }
+
+    Future<void> press(WidgetTester tester, LogicalKeyboardKey key) async {
+      await tester.sendKeyDownEvent(key);
+      await tester.sendKeyUpEvent(key);
+      await tester.pumpAndSettle();
+    }
+
+    Future<void> hold(WidgetTester tester, LogicalKeyboardKey key) async {
+      await tester.sendKeyDownEvent(key);
+      await tester.sendKeyRepeatEvent(key);
+      await tester.sendKeyRepeatEvent(key);
+      await tester.sendKeyUpEvent(key);
+      await tester.pumpAndSettle();
+    }
+
+    String? current() => stubDeps.browser.currentPage.value?.url;
+
+    ScrollPosition pageScroll(WidgetTester tester) => tester
+        .state<ScrollableState>(find
+            .descendant(of: find.byType(ListView), matching: find.byType(Scrollable))
+            .first)
+        .position;
+
+    testWidgets('Left and Right walk the links, the center opens one',
+        (tester) async {
+      await openA(tester);
+
+      await press(tester, LogicalKeyboardKey.arrowRight);
+      await press(tester, LogicalKeyboardKey.arrowRight);
+      await press(tester, LogicalKeyboardKey.arrowLeft);
+      await press(tester, LogicalKeyboardKey.select);
+      expect(current(), 'https://example.com/b.html');
+
+      debugDefaultTargetPlatformOverride = null;
+    });
+
+    testWidgets('holding Left, Right and the center navigates', (tester) async {
+      await openA(tester);
+      await stubDeps.browser.open('https://example.com/b.html');
+      await tester.pumpAndSettle();
+
+      await hold(tester, LogicalKeyboardKey.arrowLeft);
+      expect(current(), 'https://example.com/a.html');
+      await hold(tester, LogicalKeyboardKey.arrowRight);
+      expect(current(), 'https://example.com/b.html');
+      await hold(tester, LogicalKeyboardKey.select);
+      expect(current(), MewsUrls.hub);
+
+      debugDefaultTargetPlatformOverride = null;
+    });
+
+    testWidgets('Up and Down scroll, and the walk starts from the screen',
+        (tester) async {
+      await openA(tester);
+      final scroll = pageScroll(tester);
+
+      await press(tester, LogicalKeyboardKey.arrowDown);
+      expect(scroll.pixels, greaterThan(0));
+      await press(tester, LogicalKeyboardKey.arrowUp);
+      expect(scroll.pixels, 0);
+
+      // Scrolled to the end, Right takes the first link on screen rather
+      // than the first of the page.
+      scroll.jumpTo(scroll.maxScrollExtent);
+      await tester.pumpAndSettle();
+      await press(tester, LogicalKeyboardKey.arrowRight);
+      await press(tester, LogicalKeyboardKey.enter);
+      expect(current(), 'https://example.com/c.html');
+
+      debugDefaultTargetPlatformOverride = null;
+    });
+
+    testWidgets('the walk passes through form controls', (tester) async {
+      await openA(tester);
+      FocusNode? focused() => FocusManager.instance.primaryFocus;
+
+      await press(tester, LogicalKeyboardKey.arrowRight);
+      await press(tester, LogicalKeyboardKey.arrowRight);
+      await press(tester, LogicalKeyboardKey.arrowRight);
+      final field = tester.widget<EditableText>(find.descendant(
+          of: find.byType(TextFormField), matching: find.byType(EditableText)));
+      expect(focused(), field.focusNode);
+
+      // Typed text keeps Left for its cursor until the cursor is at the start.
+      await tester.enterText(find.byType(TextFormField), 'Al');
+      await press(tester, LogicalKeyboardKey.arrowRight);
+      expect(focused()?.context?.findAncestorWidgetOfExactType<FilledButton>(),
+          isNotNull);
+      await press(tester, LogicalKeyboardKey.arrowLeft);
+      expect(focused(), field.focusNode);
+      await press(tester, LogicalKeyboardKey.arrowLeft);
+      await press(tester, LogicalKeyboardKey.arrowLeft);
+      expect(focused(), field.focusNode);
+      await press(tester, LogicalKeyboardKey.arrowLeft);
+      expect(field.focusNode.hasFocus, isFalse);
+      await press(tester, LogicalKeyboardKey.select);
+      expect(current(), 'https://example.com/c.html');
+
+      debugDefaultTargetPlatformOverride = null;
+    });
+
+    testWidgets('the arrows reach the buttons of an error page', (tester) async {
+      await openA(tester);
+      await stubDeps.browser.open('https://example.com/missing.html');
+      await tester.pumpAndSettle();
+      expect(find.text('Try again'), findsOneWidget);
+
+      // The first button takes the focus, and the arrows move between them.
+      BuildContext? focused() => FocusManager.instance.primaryFocus?.context;
+      expect(focused()?.findAncestorWidgetOfExactType<FilledButton>(), isNotNull);
+      await press(tester, LogicalKeyboardKey.arrowDown);
+      expect(focused()?.findAncestorWidgetOfExactType<OutlinedButton>(), isNotNull);
+
+      debugDefaultTargetPlatformOverride = null;
+    });
+
+    testWidgets('Menu shows the chrome and Down returns to the page',
+        (tester) async {
+      await openA(tester);
+      final scroll = pageScroll(tester);
+      await press(tester, LogicalKeyboardKey.arrowDown);
+      expect(find.byType(AddressBar), findsNothing);
+
+      await press(tester, LogicalKeyboardKey.contextMenu);
+      final address = tester.widget<TextField>(find.byType(TextField).first);
+      expect(address.focusNode!.hasFocus, isTrue);
+
+      // Right moves past the text to the bar's buttons.
+      await press(tester, LogicalKeyboardKey.arrowRight);
+      await press(tester, LogicalKeyboardKey.arrowRight);
+      expect(address.focusNode!.hasFocus, isFalse);
+      await press(tester, LogicalKeyboardKey.arrowLeft);
+      expect(address.focusNode!.hasFocus, isTrue);
+
+      final before = scroll.pixels;
+      await press(tester, LogicalKeyboardKey.arrowDown);
+      expect(address.focusNode!.hasFocus, isFalse);
+      await press(tester, LogicalKeyboardKey.arrowDown);
+      expect(scroll.pixels, greaterThan(before));
+
+      debugDefaultTargetPlatformOverride = null;
+    });
+  });
+
   testWidgets('bookmarks can be searched and removed from their own page',
       (tester) async {
     await pumpApp(tester);