Test against screen configuration changes with the Espresso Device API

Use the Espresso Device API to test your app when the device undergoes common configuration changes, such as rotation and screen unfolding. The Espresso Device API is the recommended tool for performing device-level actions alongside your Jetpack Compose testing rules. If you're new to writing UI tests for Jetpack Compose, see Testing your Compose layout.

The Espresso Device API lets you trigger configuration changes on a virtual device and execute your tests synchronously, so only one UI action or assertion happens at a time and your test results are more reliable. If you're new to writing UI tests with Espresso, see its documentation.

To use the Espresso Device API, you need the following:

• Android Studio Iguana or higher
• Android Gradle plugin 8.3 or higher
• Android Emulator 33.1.10 or higher
• Android virtual device that runs API level 24 or higher

Set up your project for the Espresso Device API

To set up your project so it supports the Espresso Device API, do the following:

1. To let the test pass commands to the test device, add the required network permissions to the manifest file in the androidTest source set:

   <uses-permissionandroid:name="android.permission.INTERNET"/>
   <uses-permissionandroid:name="android.permission.ACCESS_NETWORK_STATE"/>
   

   If your test targets Android 17 (API level 37) or higher, you must also declare the ACCESS_LOCAL_NETWORK permission:

   <uses-permissionandroid:name="android.permission.ACCESS_LOCAL_NETWORK"/>
   

2. Enable the enableEmulatorControl experimental flag in the gradle.properties file:

   android.experimental.androidTest.enableEmulatorControl=true
   

3. Enable the emulatorControl option in the module-level build script:

   Kotlin

   testOptions{
   emulatorControl{
   enable=true
   }
   }
   

   Groovy

   testOptions{
   emulatorControl{
   enable=true
   }
   }
   

4. In the module-level build script, import the Espresso Device library into your project:

   Kotlin

   dependencies{
   androidTestImplementation("androidx.test.espresso:espresso-device:1.1.0")
   }

   Groovy

   dependencies{
   androidTestImplementation'androidx.test.espresso:espresso-device:1.1.0'
   }

Test against common configuration changes

The Espresso Device API has multiple screen orientation and foldable states that you can use to trigger device configuration changes. The following examples show how to trigger these device states and verify the resulting UI changes using Compose test rules.

Test against screen rotation

To test screen rotation, you can use the ScreenOrientationRule class to define the device orientation during your test.

Here's an example of how to test what happens to your app when the device screen rotates:

1. First, define your Compose test rule and use the ScreenOrientationRule class to set the device to a consistent starting state (like portrait mode):

   importandroidx.compose.ui.test.assertIsDisplayed
   importandroidx.compose.ui.test.assertDoesNotExist
   importandroidx.compose.ui.test.junit4.createComposeRule
   importandroidx.compose.ui.test.onNodeWithTag
   importandroidx.test.espresso.device.EspressoDevice.onDevice
   importandroidx.test.espresso.device.action.ScreenOrientation
   importandroidx.test.espresso.device.rules.ScreenOrientationRule
   importorg.junit.Rule
   importorg.junit.Test
   classMyConfigurationTest{
   // 1. Define the Compose test rule
   @get:Rule
   valcomposeTestRule=createComposeRule()
   // 2. Define the Espresso Device rule for a consistent starting state
   @get:Rule
   valscreenOrientationRule=ScreenOrientationRule(ScreenOrientation.PORTRAIT)
   }
   

   If your test targets Android 17 (API level 37) or higher, the Espresso Device API requires the ACCESS_LOCAL_NETWORK permission. You must ensure this permission is granted before the ScreenOrientationRule rule runs. Use JUnit's RuleChain to run the GrantPermissionRule rule first:

   importandroidx.test.rule.GrantPermissionRule
   importorg.junit.rules.RuleChain
   classMyConfigurationTest{
   valgrantPermissionRule=GrantPermissionRule.grant(android.Manifest.permission.ACCESS_LOCAL_NETWORK)
   valcomposeTestRule=createComposeRule()
   valscreenOrientationRule=ScreenOrientationRule(ScreenOrientation.PORTRAIT)
   @get:Rule
   valchain=RuleChain
   .outerRule(grantPermissionRule)
   .around(composeTestRule)
   .around(screenOrientationRule)
   }
   

2. Create a test that sets the device to landscape orientation during test execution:

   @Test
   funmyRotationTest(){
   ...
   // Sets the device to landscape orientation during test execution.
   onDevice().setScreenOrientation(ScreenOrientation.LANDSCAPE)
   ...
   }
   

3. After the screen rotates, use composeTestRule to check that your composables adapt to the new state as expected.

   @Test
   funmyRotationTest(){
   ...
   // Sets the device to landscape orientation during test execution.
   onDevice().setScreenOrientation(ScreenOrientation.LANDSCAPE)
   composeTestRule.onNodeWithTag("NavRail").assertIsDisplayed()
   composeTestRule.onNodeWithTag("BottomBar").assertDoesNotExist()
   }
   

Test against screen unfolding

Here's an example of how to test what happens to your app if it's on a foldable device and the screen unfolds:

1. First, test with the device in the folded state by calling onDevice().setClosedMode(). Make sure that your composables adapt to the compact screen width.

   @Test
   funmyUnfoldedTest(){
   onDevice().setClosedMode()
   composeTestRule.onNodeWithTag("BottomBar").assertIsDisplayed()
   composeTestRule.onNodeWithTag("NavRail").assertDoesNotExist()
   ...
   }
   

2. To transition to a fully unfolded state, call onDevice().setFlatMode(). Check that the composables adapt to the expanded size class.

   @Test
   funmyUnfoldedTest(){
   onDevice().setClosedMode()
   ...
   onDevice().setFlatMode()
   composeTestRule.onNodeWithTag("NavRail").assertIsDisplayed()
   composeTestRule.onNodeWithTag("BottomBar").assertDoesNotExist()
   }
   

Specify what devices your tests need

If you're running a test that performs folding actions on a device that isn't foldable, the test will likely fail. To execute only the tests that are relevant to the running device, use the @RequiresDeviceMode annotation. The test runner automatically skips running tests on devices that don't support the configuration being tested. You can add the device requirement rule to each test or an entire test class.

For example, to specify that a test should only be run on devices that support unfolding to a flat configuration, add the following @RequiresDeviceMode code to your test:

@Test
@RequiresDeviceMode(mode=FLAT)
funmyUnfoldedTest(){
...
}