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 and flakiness of an emulator. Robolectric tests routinely run 10x faster than those on cold-started emulators.

Robolectric supports running unit tests for 14 different versions of Android, ranging from Lollipop (API level 21) to U (API level 34).

Usage

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

@RunWith(AndroidJUnit4.class)
public class MyActivityTest {

  @Test
  public void clickingButton_shouldChangeResultsViewText() {
    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 "junit:junit:4.13.2"
testImplementation "org.robolectric:robolectric:4.12.2"

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.

To get a high-level overview of Robolectric's architecture, check out ARCHITECTURE.md.

Prerequisites

See Building Robolectric for more details about setting up a build environment for Robolectric.

Building

Robolectric supports running tests against multiple Android API levels. To build Robolectric, run:

./gradlew clean assemble testClasses --parallel

Testing

Run tests for all API levels:

The fully tests could consume more than 16G memory(total of physical and virtual memory).

./gradlew test --parallel

Run tests for part of supported API levels, e.g. run tests for API level 26, 27, 28:

./gradlew test --parallel "-Drobolectric.enabledSdks=26,27,28"

Run compatibility test suites on opening Emulator:

./gradlew connectedCheck

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:4.13-SNAPSHOT"
}