anchor.diff:  import 'dart:io';
   
   import 'package:flutter/material.dart';
  +import 'package:flutter_test/flutter_test.dart';
   import 'package:get_it/get_it.dart';
  -import 'package:flutter_test/flutter_test.dart';
   import 'package:http/http.dart';
   import 'package:mockito/mockito.dart';
   import 'package:polaris/api/api.dart';
  
positive.code:         find.widgetWithText(TextFormField, 'Server URL');
      final Finder connectButton = find.widgetWithText(ElevatedButton, 'CONNECT');
  
      final badURL = 'bad-polaris-url';
      final client = getIt<Client>();
      when(client.get(badURL + '/api/version')).thenThrow('bad host');
  
      await tester.enterText(urlInputField, badURL);
      await tester.tap(connectButton);
      await tester.pump();
      expect(find.widgetWithText(SnackBar, errorNetwork), findsOneWidget);
    });
  }
  
negative.code: 
  class MockClient extends Mock implements Client {}
  
  final host = 'my-polaris-server';
  
  Future _setup() async {
    SharedPreferences.setMockInitialValues(Map<String, dynamic>());
  
    var host = await Host.create();
    getIt.allowReassignment = true;
    getIt.registerSingleton<Host>(host);
    getIt.registerSingleton<Client>(MockClient());
    getIt.registerSingleton<API>(HttpAPI());
  