[cloud firestore] Unit testing FutureBuilder with get() fails test

[chunyongg]

I have a simple widget I created for testing

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';

class DummyTest extends StatefulWidget {
  final FirebaseFirestore firestore;
  DummyTest({this.firestore});

  @override
  _DummyTestState createState() => _DummyTestState();
}

class _DummyTestState extends State<DummyTest> {
  @override
  Widget build(BuildContext context) {
    return FutureBuilder<DocumentSnapshot>(
        future: widget.firestore.collection('test').doc('abc').get(),
        builder: (context, future) {
          if (future.hasError) {
            return Center(child: Text(future.error));
          } else if (!future.hasData) {
            return Center(child: CircularProgressIndicator());
          } else {
            return Text(future.data.exists.toString());
          }
        });
  }
}

and this is my test code

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:mockito/mockito.dart';
import 'package:vibefam/components/studioprofile/dummytest.dart';

class MockFirestore extends Mock implements FirebaseFirestore {}

class MockCollectionReference extends Mock implements CollectionReference {}

class MockDocumentReference extends Mock implements DocumentReference {}

class MockDocumentSnapshot extends Mock implements DocumentSnapshot {}

void main() {

  testWidgets('Widget renders false Text', (WidgetTester tester) async {
    final MockFirestore firestore = MockFirestore();
    final CollectionReference reference = MockCollectionReference();
    final DocumentReference documentReference = MockDocumentReference();
    final DocumentSnapshot snapshot = MockDocumentSnapshot();
    when(firestore.collection('test')).thenReturn(reference);
    when(reference.doc('abc')).thenReturn(documentReference);
    when(documentReference.get()).thenAnswer((_) => Future.value(snapshot));
    when(snapshot.exists).thenReturn(false);
    await tester.pumpWidget(MaterialApp(home: DummyTest(firestore: firestore)));
    expect(find.text(false.toString()), findsOneWidget);
  });
}

Expected outcome: Test passes

Actual outcome:

Expected: exactly one matching node in the widget tree Actual: _TextFinder:<zero widgets with text "False" (ignoring offstage widgets)> Which: means none were found but one was expected

Would appreciate some feedback!!