Configuring Testify to run on Gradle managed device

Starting from API levels 27 Android Gradle Plugin allows you to configure virtual test devices in your project's Gradle files . This feature improves testing experience by delegating the task of starting, shutting down and managing emulator to the Gradle.

When using a Gradle Managed Device, you must use the Test storage service to save screenshots. Using this service, the Android Gradle Plugin will be able to save test output to your local build folder.

Adding Gradle managed device configuration to build file

To create new Gradle managed device add it's definition to the build.gradle file:

android {
    testOptions {
        managedDevices {
            devices {
                NAME_OF_THE_DEVICE(com.android.build.api.dsl.ManagedVirtualDevice) {
                    device = "Pixel 2"
                    apiLevel = 30
                    systemImageSource = "aosp"
                }
            }
        }
    }
}

In order to receive screenshots after test execution enable TestStorageService:

android {
    defaultConfig {
        testInstrumentationRunnerArguments useTestStorageService: "true"
    }
}

dependencies {
    androidTestUtil("androidx.test.services:test-services:1.4.2")
}

With that changes applied, several new Gradle tasks will be added to your project. For a device named myDevice, then Gradle tasks myDeviceCheck and myDeviceDebugAndroidTest tasks will be added to your project.

Configuring the Testify library

You also need to instruct Testify to use Test Storage to store screenshots and diffs. This is done using Testify plugin configuration by setting the useTestStorage Gradle property to true :

testify {
    useTestStorage = true
}

Running screenshot tests

To perform screenshot test verification, run any of the new Gradle tasks, for example ./gradlew app:myDeviceDebugAndroidTest.

Because we need to run specific Gradle tasks to execute our tests using the Gradle Managed Device, we cannot use screenshotPull task. When execution is completed, navigate to the module's build/outputs/managed_device_android_test_additional_output/myDevice folder to find the recorded screenshots or diffs.

Updating baselines

Because we need to run specific Gradle tasks to execute our tests using the Gradle Managed Device, we cannot use screenshotRecord task.

To generate new baseline there are two options:

1. Apply necessary configuration on the ScreenshotRule:

ScreenshotTestRule

@get:Rule
val rule = ScreenshotRule(ClientListActivity::class.java)

@ScreenshotInstrumentation
@Test
fun testMissingBaseline() {
    rule
        .configure { 
            isRecordMode = true
        }
        .assertSame()
}

ScreenshotScenarioRule

@get:Rule
var rule = ScreenshotScenarioRule()

@ScreenshotInstrumentation
@Test
fun testMissingBaseline() {
    launchActivity<ClientListActivity>().use { scenario ->
        rule
            .withScenario(scenario)
            .configure { 
                isRecordMode = true
            }
            .assertSame()
    }
}

2. Enable record mode in the build.gradle file:

testify {
    recordMode = true
}

tip

As we cannot use screenshotPull task, when test execution is completed, the Test Storage service will copy recorded files from the module's build/outputs/managed_device_android_test_additional_output/myDevice into your androidTest/assets/screenshots/ directory.

Sample

Please check provided sample .

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