/mockito

Mocking framework for unit tests written in Java

Primary LanguageJavaMIT LicenseMIT

Mockito

simplier & better mocking

Build Status Coverage Status Current release Maven Central

Current release

See the release notes page and latest documentation.

JDK8 status

Mockito should work fine with JDK8 if you stay away from defender methods. Lambda usage may work just as good for Answers. We're unsure about every JDK8 features at the moment, like serializing a mock that uses a lambda. Error report and pull request are welcome though (contributing guide).

Moving to github

We are currently moving a few stuff from Google Code to Github.

For now only the code repository is moved, other stuff will follow like the wiki pages. Documentation may or may not follow. But discussion group, issue tracker will stay at google (unfortunatley GH PR counters incremented before we had the chance to move our issues).

Why drink it?

Mockito is a mocking framework that tastes really good. It lets you write beautiful tests with clean & simple API. Mockito doesn't give you hangover because the tests are very readable and they produce clean verification errors. Read more about features & motivations.

"We decided during the main conference that we should use JUnit 4 and Mockito because we think they are the future of TDD and mocking in Java" - Dan North, the originator of BDD

More quotes

Over 15000 downloads of 1.9.0 version ('12), excluding maven/Gradle users. For latest figures see the downloads.

More about the user base

How do I drink it?

Recommended way of getting Mockito is declaring a dependency on "mockito-core" library (not "mockito-all"!) using your favorite build system. My favorite build system happens to be Gradle and so I do:

repositories {
  jcenter()
}

dependencies {
  testCompile "org.mockito:mockito-core:1.+"
}

For legacy builds with manual dependency management it might be useful to use mockito-all package that can be downloaded from Mockito's Bintray repository or Bintray's jcenter.

For more information please refer to the wiki page.

Then you can verify interactions

import static org.mockito.Mockito.*;

// mock creation
List mockedList = mock(List.class);

// using mock object ; observe that it didn't throw any "unexpected interaction exception" exception
mockedList.add("one");
mockedList.clear();

// selective & explicit verification
verify(mockedList).add("one");
verify(mockedList).clear();

Or stub method calls

// you can mock concrete classes, not only interfaces
LinkedList mockedList = mock(LinkedList.class);

// stubbing; before the actual execution
when(mockedList.get(0)).thenReturn("first");

// the following prints "first"
System.out.println(mockedList.get(0));

// the following prints "null" because get(999) was not subbed
System.out.println(mockedList.get(999));

You can go further

Main reference documentation features:

  • mock()/@Mock: Create a mock (specify how it should behave via Answer/ReturnValue/MockSettings)
    • when()/given() to specify how a mock should behave.
    • If the provided answers doesn't fit your needs, write one yourself extending the Answer interface
  • spy()/@Spy: Calls a real object but records what has been called,
  • @InjectMocks: Used as a kind of simple automatic dependency injection of fields created using the @Spy or @Mock annotation.
  • verify() to check methods were called with given arguments; can match any expression via the any(), or capture what arguments where called using @Captor instead.
  • Try BDD syntax with BDDMockito
  • Try the Mockito on Android, thanks to the Google guys working on dexmaker (more on that later)

Remember

  • Do not mock types you don't own
  • Don't mock value objects
  • Don't mock everything
  • Show some love with your tests

Click here for more documentation and examples. Remember all documentation lives in javadocs so you don’t need to visit that page too often. You can grab the RefCard here.

If you have any suggestions, find documentation unclear or you found a bug, write to our mailing list. You can report bugs here.

Who is your bartender?

Mockito is served to you by Szczepan Faber and friends. First people who tried Mockito were developers of the Guardian project in London in early 2008. Here is how Szczepan explained why we need another mocking framework?

Firstly, hats down before EasyMock folks for their ideas on beautiful and refactorable mocking syntax. First hacks on Mockito were done on top of the EasyMock? code.

Here are just some of my friends who contributed ideas to Mockito (apologize if I missed somebody): Igor Czechowski, Patric Fornasier, Jim Barritt, Felix Leipold, Liz Keogh, Bartosz Bańkowski.

Now some other people joined the gang : Brice Dutheil then David Wallace.

Special thanks to Erik Ramfelt, and Steve Christou for putting Mockito on there Jenkins server (continuous integration) for a few years. Now Travis and Coveralls took over.

Thanks to Karol Poźniak for the logo :)

Finally, thanks to Erik Brakkee who helps us getting jars to maven central

links wrap-up

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