Mock dependencies in Flutter - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the mockito package for mocking dependencies in Flutter tests.

Flutter

import '[1]';

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Apackage:flutter_test/flutter_test.dart

Bpackage:flutter/material.dart

Cpackage:mockito/mockito.dart

Dpackage:test/test.dart

Attempts:

3 left

💡 Hint

Common Mistakes

Importing flutter_test instead of mockito.

Using the material package import by mistake.

The mockito package is imported with 'package:mockito/mockito.dart' to create mock classes for testing.

2fill in blank

medium

Complete the code to create a mock class for a dependency named ApiService.

Flutter

class MockApiService extends [1] implements ApiService {}

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AFake

BMock

CWidget

DStatelessWidget

Attempts:

3 left

💡 Hint

Common Mistakes

Extending Fake instead of Mock.

Trying to extend Widget or StatelessWidget.

Mockito requires mock classes to extend the Mock class to provide mocking behavior.

3fill in blank

hard

Fix the error in the test setup by completing the code to register the mock ApiService with the dependency injector.

Flutter

setUp(() {
  [1](MockApiService());
});

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AregisterSingleton

BregisterFactory

CregisterLazySingleton

DregisterProvider

Attempts:

3 left

💡 Hint

Common Mistakes

Using registerLazySingleton which expects a factory function.

Using registerFactory which creates new instances every time.

registerSingleton registers the provided mock instance directly as a singleton, suitable for test setups.

4fill in blank

hard

Fill both blanks to stub the getData method of the mock ApiService to return a Future with 'Hello'.

Flutter

when(mockApiService.[1]()).thenAnswer((_) async => [2]);

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AgetData

BfetchData

CFuture.value('Hello')

DFuture.delayed(Duration(seconds: 1), () => 'Hello')

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong method name like fetchData.

Returning a plain string instead of a Future.

The method getData is stubbed to return a Future with the string 'Hello' using Future.value.

5fill in blank

hard

Fill both blanks to verify that the getData method was called exactly once on the mock ApiService.

Flutter

verify(mockApiService.[1]()).called([2]);

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AgetData

BfetchData

C1

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong method name in verify.

Using called(2) when only one call was made.

The verify function checks that getData was called exactly once using called(1).