Robolectric is the industry-standard unit testing framework for Android. With Robolectric, your tests run in a simulated Android environment inside a JVM, without the overhead of an emulator.

Usage

Here's an example of a simple test written using Robolectric:

@RunWith(RobolectricTestRunner.class)
public class MyActivityTest {

  @Test
  public void clickingButton_shouldChangeResultsViewText() throws Exception {
    Activity activity = Robolectric.setupActivity(MyActivity.class);

    Button button = (Button) activity.findViewById(R.id.press_me_button);
    TextView results = (TextView) activity.findViewById(R.id.results_text_view);

    button.performClick();
    assertThat(results.getText().toString(), equalTo("Testing Android Rocks!"));
  }
}

For more information about how to install and use Robolectric on your project, extend its functionality, and join the community of contributors, please visit http://robolectric.org.

Install

Starting a New Project

If you'd like to start a new project with Robolectric tests you can refer to deckard (for either maven or gradle) as a guide to setting up both Android and Robolectric on your machine.

build.gradle:

testImplementation "org.robolectric:robolectric:4.1"

Building And Contributing

Robolectric is built using Gradle. Both IntelliJ and Android Studio can import the top-level build.gradle file and will automatically generate their project files from it.

You will need to have portions of the Android SDK available in your local Maven artifact repository in order to build Robolectric. Copy all required Android dependencies to your local Maven repo by running:

./scripts/install-dependencies.rb

Note: You'll need Maven installed, ANDROID_HOME set and to have the SDK and Google APIs for API Level 27 downloaded to do this.

Robolectric supports running tests against multiple Android API levels. The work it must do to support each API level is slightly different, so its shadows are built separately for each. To build shadows for every API version, run:

./gradlew clean assemble install compileTest

Using Snapshots

If you would like to live on the bleeding edge, you can try running against a snapshot build. Keep in mind that snapshots represent the most recent changes on master and may contain bugs.

build.gradle:

repositories {
    maven { url "https://oss.sonatype.org/content/repositories/snapshots" }
}

dependencies {
    testImplementation "org.robolectric:robolectric:4.2-SNAPSHOT"
}