Teste ContactListBack retorna zero widgets

Estou com um erro no teste quando ele cria um contato e deve retornar para a Lista de Contatos. Ele exibe este erro:

The following TestFailure object was thrown running a test:
  Expected: exactly one matching node in the widget tree
  Actual: _WidgetTypeFinder:<zero widgets with type "ContactsList" (ignoring offstage widgets)>
   Which: means none were found but one was expected

Ja converti a ContactsList para StatefulWidget e não corrigiu o problema.

Aqui meu arquivo de teste:

@GenerateMocks([ContactDao])
void main() {
  testWidgets('Should save a contact', (tester) async {
    final mockContactDao = MockContactDao();

    when(mockContactDao.findAll()).thenAnswer((_) async => []);
    when(mockContactDao.save(any)).thenAnswer((_) async => 1);
    await tester.pumpWidget(BytebankApp(
      contactDao: mockContactDao,
    ));

   [...]

    final contactForm = find.byType(ContactForm);
    expect(contactForm, findsOneWidget);

    final nameTextField = find.byWidgetPredicate((widget) {
      if (widget is TextField) {
        return widget.decoration!.labelText == 'Full name';
      }
      return false;
    });
    expect(nameTextField, findsOneWidget);
    await tester.enterText(nameTextField, 'Alex');

    final accountNumberTextField = find.byWidgetPredicate((widget) {
      if (widget is TextField) {
        return widget.decoration!.labelText == 'Account number';
      }
      return false;
    });
    expect(accountNumberTextField, findsOneWidget);
    await tester.enterText(accountNumberTextField, '1000');

    final createButton = find.widgetWithText(ElevatedButton, 'Create');
    expect(createButton, findsOneWidget);
    await tester.tap(createButton);
    await tester.pumpAndSettle();

    final contactsListBack = find.byType(ContactsList);
    expect(contactsListBack, findsOneWidget);
  });
}

ContactsList

class ContactsList extends StatefulWidget {
  final ContactDao contactDao;

  ContactsList({required this.contactDao});

  @override
  _ContactsListState createState() =>
      _ContactsListState(contactDao: contactDao);
}

class _ContactsListState extends State<ContactsList> {
  final ContactDao contactDao;

  _ContactsListState({required this.contactDao});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Transfer'),
      ),
      body: FutureBuilder<List<Contact>>(
        initialData: [],
        future: widget.contactDao.findAll(),
        builder: (context, snapshot) {
          switch (snapshot.connectionState) {
            case ConnectionState.none:
              break;
            case ConnectionState.waiting:
              return Progress();
              break;
            case ConnectionState.active:
              break;
            case ConnectionState.done:
              final List<Contact>? contacts = snapshot.data;
              return ListView.builder(
                itemBuilder: (context, index) {
                  final Contact contact = contacts![index];
                  return _ContactItem(
                    contact,
                    onClick: () {
                      Navigator.of(context).push(
                        MaterialPageRoute(
                          builder: (context) => TransactionForm(contact),
                        ),
                      );
                    },
                  );
                },
                itemCount: contacts!.length,
              );
              break;
          }
          return Text('Unknown error');
        },
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          Navigator.of(context)
              .push(MaterialPageRoute(
                  builder: (context) => ContactForm(contactDao: contactDao)))
              .then((newContact) {
            if (newContact != null) {
              setState(() {
                contactDao.findAll();
              });
            }
          });
        },
        child: Icon(
          Icons.add,
        ),
      ),
    );
  }
}

class _ContactItem extends StatelessWidget {
  final Contact contact;
  final Function onClick;

  _ContactItem(
    this.contact, {
    required this.onClick,
  });

  @override
  Widget build(BuildContext context) {
    return Card(
      child: ListTile(
        onTap: () => onClick(),
        title: Text(
          contact.name,
          style: TextStyle(
            fontSize: 24.0,
          ),
        ),
        subtitle: Text(
          contact.accountNumber.toString(),
          style: TextStyle(
            fontSize: 16.0,
          ),
        ),
      ),
    );
  }
}