Roborazzi

Make JVM Android Integration Test Visible

Roborazzi now supports Robolectric Native Graphics (RNG) and enables screenshot testing.📣

Why Choose Roborazzi?

Why is screenshot testing important?

Screenshot testing is key to validate your app's appearance and functionality. It efficiently detects visual issues and tests the app as users would use it, making it easier to spot problems. It's quicker than writing many assert statements, ensuring your app looks right and behaves correctly.

What are JVM tests and why test with JVM instead of on Android?

JVM tests, also known as local tests, are placed in the test/ directory and are run on a developer's PC or CI environment. On the other hand, device tests, also known as Instrumentation tests, are written in the androidTest/ directory and are run on real devices or emulators. Device testing can result in frequent failures due to the device environment, leading to false negatives. These failures are often hard to reproduce, making them tough to resolve.

Paparazzi and Roborazzi: A Comparison

Paparazzi is a great tool for visualizing displays within the JVM. However, it's incompatible with Robolectric, which also mocks the Android framework.

Roborazzi fills this gap. It integrates with Robolectric, allowing tests to run with Hilt and interact with components. Essentially, Roborazzi enhances Paparazzi's capabilities, providing a more efficient and reliable testing process by capturing screenshots with Robolectric.

Leveraging Roborazzi in Test Architecture: An Example

Integrating Roborazzi into the Architecture: An Example from DroidKaigi 2023 App

In the DroidKaigi 2023 app, Roborazzi was introduced from the early stages of development as part of the architectural design. This integration allowed the team to verify changes throughout the development process. The specific architectural decisions and how they were implemented can be found README.

Try it out

Available on Maven Central.

Add Robolectric

This is an example of adding Robolectric to your project: https://github.com/takahirom/roborazzi-usage-examples/compare/b697...5c12

This library is dependent on Robolectric. Please see below to add Robolectric.

https://robolectric.org/getting-started/

Add Roborazzi

This is an example of adding Roborazzi to your project: https://github.com/takahirom/roborazzi-usage-examples/commit/3a02

To take screenshots, please use Robolectric 4.10 alpha 1 or later and please add @GraphicsMode(GraphicsMode.Mode.NATIVE) to your test class.

@GraphicsMode(GraphicsMode.Mode.NATIVE)

Build setup

Roborazzi is available on maven central.

This plugin simply creates Gradle tasks record, verify, compare and passes the configuration to the test.

build.gradle.kts

plugins {
  ...
  id("io.github.takahirom.roborazzi") version "[version]" apply false
}

plugins {
  ...
  id("io.github.takahirom.roborazzi")
}

buildscript {
  dependencies {
    ...
    classpath("io.github.takahirom.roborazzi:roborazzi-gradle-plugin:[version]")
  }
}

plugins {
    ...
    id("io.github.takahirom.roborazzi")
}

plugins {
  ...
  id "io.github.takahirom.roborazzi" version "[version]" apply false
}

plugins {
  ...
  id 'io.github.takahirom.roborazzi'
}

buildscript {
  dependencies {
    ...
    classpath "io.github.takahirom.roborazzi:roborazzi-gradle-plugin:[version]"
  }
}

apply plugin: "io.github.takahirom.roborazzi"

The comparison image, saved as [original]_compare.png, is shown below:

You can check the test report in build/reports/roborazzi/index.html

This uses JetNew from Compose Samples. You can check the pull request introducing Roborazzi to the compose-samples here.

Gradle DSL Options (Optional)

roborazzi {
  // Directory for reference images
  outputDir.set(file("src/screenshots"))
  // Directory for comparison images (Experimental option)
  compare {
    outputDir.set(file("build/outputs/screenshots_comparison"))
  }
}

[!NOTE]

By default, when you use captureRoboImage("image.png"), the image will be saved as module/image.png.

You can customize the file path strategy for the recorded image. The default strategy is relativePathFromCurrentDirectory. If you select relativePathFromRoborazziContextOutputDirectory, the file will be saved in the output directory specified by roborazzi.outputDir.

This can be configured in your gradle.properties file:

> roborazzi.record.filePathStrategy=relativePathFromRoborazziContextOutputDirectory

Separate output directories per variant/target (Experimental)

By default, every Roborazzi task shares a single output directory (build/outputs/roborazzi) and a single intermediate directory (build/intermediates/roborazzi). When multiple Roborazzi test tasks run in a single Gradle invocation (for example check, or Kotlin Multiplatform's allTests), their directory reads and writes can race with each other. On Gradle 9 this can hard-fail with Cannot access input property 'roborazziImageInput' (see #830).

Enabling separateOutputDirs gives each task slug its own subdirectory, so the tasks never share a directory:

roborazzi {
  // Experimental
  separateOutputDirs.set(true)
}

The unit of separation is the recordRoborazzi<Slug> slug:

• Android: the variant name, e.g. build/outputs/roborazzi/debug/, build/outputs/roborazzi/release/.
• Kotlin Multiplatform: the target (× test run) name, e.g. build/outputs/roborazzi/desktop/.

[!IMPORTANT]

Enabling this option changes where golden images are stored. Existing users must re-record (or manually move) their goldens into the new per-slug subdirectory, otherwise verification will not find them. This is opt-in and defaults to false, so existing behavior is unchanged unless you enable it.

This also partially addresses requests for per-flavor/variant subdirectories (#804, #731).

Add dependencies

| Description | Dependencies | |-----------------|--------------------------------------------------------------------------------------| | Core functions | testImplementation("io.github.takahirom.roborazzi:roborazzi:[version]") | | Jetpack Compose | testImplementation("io.github.takahirom.roborazzi:roborazzi-compose:[version]") | | JUnit rules | testImplementation("io.github.takahirom.roborazzi:roborazzi-junit-rule:[version]") |

How to use

Take a screenshot manually

You can take a screenshot by calling captureRoboImage().

app/src/test/java/../ManualTest.kt

import androidx.compose.ui.test.junit4.createAndroidComposeRule
import androidx.test.core.app.ActivityScenario
import androidx.test.espresso.Espresso.onView
import androidx.test.ext.junit.runners.AndroidJUnit4
import org.junit.Test
import org.junit.runner.RunWith
import org.robolectric.annotation.GraphicsMode
// All you need to do is use the captureRoboImage function in the test! import com.github.takahirom.roborazzi.captureRoboImage
// Tips: You can use Robolectric while using AndroidJUnit4 @RunWith(AndroidJUnit4::class) // Enable Robolectric Native Graphics (RNG)  @GraphicsMode(GraphicsMode.Mode.NATIVE) class ManualTest {   @get:Rule   val composeTestRule = createAndroidComposeRule<MainActivity>()
@Test   fun captureRoboImageSample() {     // Tips: You can use Robolectric with Espresso API     // launch     ActivityScenario.launch(MainActivity::class.java)
// Capture screen     onView(ViewMatchers.isRoot())       // If you don't specify a screenshot file name, Roborazzi will automatically use the method name as the file name for you.       // The format of the file name will be as follows:       // build/outputs/roborazzi/com...ManualTest_captureRoboImageSample.png       .captureRoboImage()
// Capture Jetpack Compose Node     composeTestRule.onNodeWithTag("AddBoxButton")       .onParent()       .captureRoboImage("build/compose.png")   } }

Roborazzi supports the following APIs.

composeTestRule.onNodeWithTag("AddBoxButton")
  .captureRoboImage()

onView(ViewMatchers.isRoot())
  .captureRoboImage()

onView(withId(R.id.button_first))
  .captureRoboImage()

val view: View = composeTestRule.activity.findViewById<View>(R.id.button_second)
view.captureRoboImage()

captureRoboImage() {
  Text("Hello Compose!")
}

captureScreenRoboImage()

val bitmap: Bitmap = createBitmap(100, 100, Bitmap.Config.ARGB_8888)
  .apply {
    applyCanvas {
      drawColor(android.graphics.Color.YELLOW)
    }
  }
bitmap.captureRoboImage()

Device configuration

You can configure the device by using the @Config annotation and RobolectricDeviceQualifiers.

@RunWith(AndroidJUnit4::class)
@GraphicsMode(GraphicsMode.Mode.NATIVE)
@Config(qualifiers = RobolectricDeviceQualifiers.Pixel5)
class RoborazziTest {

@Test
@Config(qualifiers = RobolectricDeviceQualifiers.Pixel5)
fun test() {

@Config(qualifiers = "+night")

@Config(qualifiers = "+ja")

@Config(qualifiers = RobolectricDeviceQualifiers.MediumTablet)

Integrate to your GitHub Actions

It is easy to integrate Roborazzi to your GitHub Actions.

Add a job to store screenshots

name: store screenshots
on:   push
env:   GRADLE_OPTS: "-Dorg.gradle.jvmargs=-Xmx6g -Dorg.gradle.daemon=false -Dkotlin.incremental=false"
jobs:   test:     runs-on: macos-latest
steps:       - uses: actions/checkout@v3       - uses: actions/setup-java@v3.9.0         with:           distribution: 'zulu'           java-version: 19
- name: Gradle cache         uses: gradle/gradle-build-action@v2
- name: test         run: |           # Create screenshots           ./gradlew app:recordRoborazziDebug --stacktrace
# Upload screenshots to GitHub Actions Artifacts       - uses: actions/upload-artifact@v3         with:           name: screenshots           path: app/build/outputs/roborazzi           retention-days: 30

Add a job to verify screenshots

name: verify test
on:   push
env:   GRADLE_OPTS: "-Dorg.gradle.jvmargs=-Xmx6g -Dorg.gradle.daemon=false -Dkotlin.incremental=false"
jobs:   test:     runs-on: macos-latest
steps:       - uses: actions/checkout@v3       - uses: actions/setup-java@v3.9.0         with:           distribution: 'zulu'           java-version: 19
- name: Gradle cache         uses: gradle/gradle-build-action@v2
# Download screenshots from main branch       - uses: dawidd6/action-download-artifact@v2         with:           name: screenshots           path: app/build/outputs/roborazzi           workflow: test.yaml           branch: main
- name: verify test         id: verify-test         run: |           # If there is a difference between the screenshots, the test will fail.           ./gradlew app:verifyRoborazziDebug --stacktrace
- uses: actions/upload-artifact@v3         if: ${{ always() }}         with:           name: screenshot-diff           path: app/build/outputs/roborazzi           retention-days: 30
- uses: actions/upload-artifact@v3         if: ${{ always() }}         with:           name: screenshot-diff-reports           path: app/build/reports           retention-days: 30
- uses: actions/upload-artifact@v3         if: ${{ always() }}         with:           name: screenshot-diff-test-results           path: app/build/test-results           retention-days: 30

Advanced workflow Sample: Compare Snapshot Results on Pull Requests

For those who are looking for a more advanced example, we have prepared a sample repository that demonstrates how to use Roborazzi to compare snapshot results on GitHub pull requests. This sample showcases the integration of Roborazzi with GitHub Actions workflows, making it easy to visualize and review the differences between snapshots directly in the pull request comments.

Check out the roborazzi-compare-on-github-comment-sample repository to see this powerful feature in action and learn how to implement it in your own projects.

Example of the comment

RoborazziRule (Optional)

RoborazziRule is a JUnit rule for Roborazzi. RoborazziRule is optional. You can use captureRoboImage() without this rule.

RoborazziRule has two features.

• Provide context such as RoborazziOptions and outputDirectoryPath etc for captureRoboImage().
• Capture screenshots for each test when specifying RoborazziRule.options.captureType.

@RunWith(AndroidJUnit4::class)
@GraphicsMode(GraphicsMode.Mode.NATIVE)
class RuleTestWithPath {
  @get:Rule
  val roborazziRule = RoborazziRule(
    options = Options(
      outputDirectoryPath = "$DEFAULTROBORAZZIOUTPUTDIRPATH/custom_outputDirectoryPath",
      outputFileProvider = { description, outputDirectory, fileExtension ->
        File(
          outputDirectory,
          "custom_outputFileProvider-${description.testClass.name}.${description.methodName}.$fileExtension"
        )
      }
    ),
  )
@Test   fun captureRoboImage() {     launch(MainActivity::class.java)     // The file will be saved using the rule's outputDirectoryPath and outputFileProvider     onView(isRoot()).captureRoboImage()   } }

Generate gif image

@Test
fun captureRoboGifSample() {
  onView(ViewMatchers.isRoot())
    .captureRoboGif("build/test.gif") {
      // launch
      ActivityScenario.launch(MainActivity::class.java)
      // move to next page
      onView(withId(R.id.button_first))
        .perform(click())
      // back
      pressBack()
      // move to next page
      onView(withId(R.id.button_first))
        .perform(click())
    }
}

Generate gif with test rule

Note

You don't need to use RoborazziRule if you're using captureRoboImage().

With the JUnit test rule, you do not need to name the gif image, and if you prefer, you can output the gif image only if the test fails.

This test will output this file.

build/outputs/roborazzi/com.github.takahirom.roborazzi.sample.RuleTestWithOnlyFail_captureRoboGifSampleFail.gif

@RunWith(AndroidJUnit4::class)
@GraphicsMode(GraphicsMode.Mode.NATIVE)
class RuleTestWithOnlyFail {
  @get:Rule
  val roborazziRule = RoborazziRule(
    captureRoot = onView(isRoot()),
    options = Options(
      onlyFail = true,
      captureType = RoborazziRule.CaptureType.Gif,
    )
  )
@Test   fun captureRoboLastImageSampleFail() {     // launch     ActivityScenario.launch(MainActivity::class.java)     // move to next page     onView(withId(R.id.button_first))       .perform(click())     // should fail because the button does not exist     // Due to failure, the gif image will be saved in the outputs folder.     onView(withId(R.id.button_first))       .perform(click())   } }

Generate Jetpack Compose gif with test rule

Test target

@Composable
fun SampleComposableFunction() {
  var count by remember { mutableStateOf(0) }
  Column(
    Modifier
      .size(300.dp)
  ) {
    Box(
      Modifier
        .testTag("AddBoxButton")
        .size(50.dp)
        .clickable {
          count++
        }
    )
    (0..count).forEach {
      Box(
        Modifier
          .size(30.dp)
      )
    }
  }
}

Test (Just add RoborazziRule)

@RunWith(AndroidJUnit4::class)
@GraphicsMode(GraphicsMode.Mode.NATIVE)
class ComposeTest {
  @get:Rule
  val composeTestRule = createAndroidComposeRule<ComponentActivity>()
@get:Rule   val roborazziRule = RoborazziRule(     composeRule = composeTestRule,     captureRoot = composeTestRule.onRoot(),     options = RoborazziRule.Options(       RoborazziRule.CaptureType.Gif()     )   )
@Test   fun composable() {     composeTestRule.setContent {       SampleComposableFunction()     }     (0 until 3).forEach { _ ->       composeTestRule         .onNodeWithTag("AddBoxButton")         .performClick()     }   } }

Record a video of the UI (experimental)

recordRoboVideo() records how the UI evolves over virtual time -- animations, transitions, gestures and any other time-driven change -- as an animated image that plays back in real time. Unlike captureRoboGif(), which only records visually distinct states with a fixed 1-second delay, it pauses the Compose main clock and drives it frame by frame, so intermediate animation frames are captured with faithful timing. Interactions in the block run with the clock paused; call delay() in the scope to advance virtual time while frames are recorded. After the block returns, recording continues until the UI settles, so a block that only performs a click still records the whole animation the click starts.

@OptIn(ExperimentalRoborazziApi::class)
@Test
fun recordVideo() {
  composeTestRule.setContent {
    AnimatedBoxContent()
  }
  composeTestRule.onNodeWithTag("root")
    .recordRoboVideo(
      composeRule = composeTestRule,
      filePath = "build/outputs/roborazzi/video.gif",
      videoOptions = RoboVideoOptions(fps = 10),
    ) {
      composeTestRule.onNodeWithTag("toggle").performClick()
      delay(300)
      composeTestRule.onNodeWithTag("toggle").performClick()
      delay(300)
    }
}

• RoboVideoOptions: fps (default 10), settleTimeoutMillis (additional virtual time to

• Output format is chosen by the file extension: .gif produces a GIF (256 colors; the

• GIF stores frame delays in centiseconds (10ms resolution), so prefer an fps whose frame step

• The API is experimental (@ExperimentalRoborazziApi) and currently only supports recording:

recordScreenRoboVideo() records all window roots instead of a single node, mirroring how captureScreenRoboImage() relates to captureRoboImage(). Prefer it when you want a stable, device-sized viewport for every frame, or to capture window overlays such as dialogs added mid-recording or touch/tap indicators, which live on separate window roots and are invisible to a node-scoped recording. Usage is the same, just without node scoping:

recordScreenRoboVideo(
  composeRule = composeTestRule,
  filePath = "build/outputs/roborazzi/video_screen.gif",
  videoOptions = RoboVideoOptions(fps = 10),
) {
  composeTestRule.onNodeWithTag("toggle").performClick()
  delay(300)
}

Because the recorder idles the Robolectric main Looper in lockstep with the Compose main clock, suspend-based gesture drivers make progress while frames are recorded. For example, you can drive a swipe with saket/touch-robot from a LaunchedEffect, use recordScreenRoboVideo() so the touch indicator overlay is captured, and just pump virtual time in the block:

composeTestRule.setContent {
  // A composable whose LaunchedEffect drives a touch-robot swipe on the root.
  DraggableBoxContent()
}
recordScreenRoboVideo(
  composeRule = composeTestRule,
  filePath = "build/outputs/roborazzi/swipe.gif",
) {
  // Pump virtual time so the LaunchedEffect gesture progresses while frames are captured.
  delay(1000)
}

RoborazziRule options

You can use some RoborazziRule options

/**
 * This rule is a JUnit rule for roborazzi.
 * This rule is optional. You can use [captureRoboImage] without this rule.
 *
 * This rule have two features.
 * 1. Provide context such as RoborazziOptions and outputDirectoryPath etc for [captureRoboImage].
 * 2. Capture screenshots for each test when specifying RoborazziRule.options.captureType.
 */
class RoborazziRule private constructor(
  private val captureRoot: CaptureRoot,
  private val options: Options = Options()
) : TestWatcher() {
  /**
   * If you add this annotation to the test, the test will be ignored by
   * roborazzi's CaptureType.LastImage, CaptureType.AllImage and CaptureType.Gif.
   */
  annotation class Ignore
data class Options(     val captureType: CaptureType = CaptureType.None,     /**      * output directory path      */     val outputDirectoryPath: String = provideRoborazziContext().outputDirectory,
val outputFileProvider: FileProvider = provideRoborazziContext().fileProvider       ?: defaultFileProvider,     val roborazziOptions: RoborazziOptions = provideRoborazziContext().options,   )
sealed interface CaptureType {     /**      * Do not generate images. Just provide the image path to [captureRoboImage].      */     object None : CaptureType
/**      * Generate last images for each test      */     data class LastImage(       /**        * capture only when the test fail        */       val onlyFail: Boolean = false,     ) : CaptureType
/**      * Generate images for Each layout change like TestClassmethod0.png for each test      */     data class AllImage(       /**        * capture only when the test fail        */       val onlyFail: Boolean = false,     ) : CaptureType
/**      * Generate gif images for each test      */     data class Gif(       /**        * capture only when the test fail        */       val onlyFail: Boolean = false,     ) : CaptureType   }

Image comparator custom settings

@get:Rule
val roborazziRule = RoborazziRule(
    options = RoborazziRule.Options(
        roborazziOptions = RoborazziOptions(
            compareOptions = RoborazziOptions.CompareOptions(
                changeThreshold = 0.01, // For 1% accepted difference
                imageComparator = SimpleImageComparator(
                    maxDistance = 0.007F, // 0.001F is default value from Differ
                    vShift = 2, // Increasing the shift can help resolve antialiasing issues
                    hShift = 2 // Increasing the shift can help resolve antialiasing issues
                )
            )
        )
    )
)

Experimental WebP support and other image formats

You can set roborazzi.record.image.extension to webp in your gradle.properties file to generate WebP images.

roborazzi.record.image.extension=webp

WebP is a lossy image format by default, which can make managing image differences challenging. To address this, we provide a lossless WebP image comparison feature. To enable WebP support, add testImplementation("io.github.darkxanter:webp-imageio:0.3.3") to your build.gradle.kts file.

onView(ViewMatchers.withId(R.id.textview_first))
  .captureRoboImage(
    roborazziOptions = RoborazziOptions(
      recordOptions = RoborazziOptions.RecordOptions(
        imageIoFormat = LosslessWebPImageIoFormat(),
      ),
    )
  )

You can also use other image formats by implementing your own AwtImageWriter and AwtImageLoader.

data class JvmImageIoFormat(
  val awtImageWriter: AwtImageWriter,
  val awtImageLoader: AwtImageLoader
) : ImageIoFormat

Dump mode

If you are having trouble debugging your test, try Dump mode as follows.

Accessibility Check

Roborazzi Accessibility Checks is a library that integrates accessibility checks into Roborazzi. Please refer to Accessibility Check

Roborazzi options

Please check out RoborazziOptions for available Roborazzi options.

Experimental Compose Preview Support

Roborazzi provides support for generating screenshot tests and easy setup for Jetpack Compose Preview. This support uses ComposablePreviewScanner to scan the Composable Previews in your project.

Generate Compose Preview screenshot tests

You first need to add the Roborazzi plugin to your project. Please refer to the setup guide for more information. Then you can enable the Compose Preview screenshot test generation feature by adding the following configuration to your build.gradle.kts file:

roborazzi {
  generateComposePreviewRobolectricTests {
    enable = true
  }
}

The plugin will not automatically change your settings or add dependencies to prevent conflicts with your existing setup. However, it will provide instructions on what to do next, such as adding dependencies and required code. You can also check the sample project for a complete example.

After that, you can run the recordRoborazziDebug task to generate screenshots using the generated tests, as described in the setup guide.

Customizing the Preview screenshot test

You can customize the generated test by adding the following configuration to your build.gradle.kts file:

roborazzi {
  @OptIn(ExperimentalRoborazziApi::class)
  generateComposePreviewRobolectricTests {
    enable = true
    // The package names to scan for Composable Previews.
    packages = listOf("com.example")
    // robolectricConfig will be passed to Robolectric's @Config annotation in the generated test class.
    // See https://robolectric.org/configuring/ for more information.
    robolectricConfig = mapOf(
      "sdk" to "[32]",
      "qualifiers" to "RobolectricDeviceQualifiers.Pixel5",
    )
    // If true, the private previews will be included in the test.
    includePrivatePreviews = true
    // The fully qualified class name of the custom test class that implements [com.github.takahirom.roborazzi.ComposePreviewTester].
    testerQualifiedClassName = "com.example.MyCustomComposePreviewTester"
    // The number of test classes to generate. Set this to match maxParallelForks for parallel test execution.
    generatedTestClassCount = 4
    // Filter previews by annotation. Defaults to AnnotationFilter.Filter.RoboPreviewExclude
    // (previews annotated with @RoboPreviewExclude are skipped). Override to switch to opt-in mode
    // where only previews annotated with @RoboPreviewInclude are captured.
    annotationFilter = AnnotationFilter.Filter.RoboPreviewInclude
  }
}

Advanced: Custom ComposePreviewTester Implementation

You can create a custom ComposePreviewTester to control the screenshot capture behavior, such as setting a custom image comparison threshold.

Note that AndroidComposePreviewTester is a final class, so you can't subclass it. Instead, use Kotlin class delegation and pass a custom Capturer to its constructor. Also, your tester class must have a parameterless constructor because the plugin instantiates it via reflection:

import com.dropbox.differ.SimpleImageComparator
import com.github.takahirom.roborazzi.*
import com.github.takahirom.roborazzi.ComposePreviewTester.TestParameter.JUnit4TestParameter.AndroidPreviewJUnit4TestParameter
@OptIn(ExperimentalRoborazziApi::class) class MyCustomComposePreviewTester :   ComposePreviewTester<AndroidPreviewJUnit4TestParameter> by AndroidComposePreviewTester(     capturer = { parameter ->       val customOptions = parameter.roborazziOptions.copy(         compareOptions = parameter.roborazziOptions.compareOptions.copy(           // Set custom comparison threshold (0.0 = exact match, 1.0 = ignore differences)           imageComparator = SimpleImageComparator(maxDistance = 0.01f)         )       )       AndroidComposePreviewTester.DefaultCapturer().capture(         parameter.copy(roborazziOptions = customOptions)       )     }   )

If you need to customize more than the capture behavior, such as the scan options or the test lifecycle, you can override options() or test() in the delegating class.

Then reference your custom tester in the Gradle configuration:

roborazzi {
  @OptIn(ExperimentalRoborazziApi::class)
  generateComposePreviewRobolectricTests {
    enable = true
    testerQualifiedClassName = "com.example.MyCustomComposePreviewTester"
  }
}

[!NOTE]

If you are using Groovy DSL instead of Kotlin DSL, you need to use the set method for each assignment:

> generateComposePreviewRobolectricTests.enable.set(true)

Filtering previews by annotation

annotationFilter controls which previews are captured (requires the roborazzi-annotations dependency). By default it is AnnotationFilter.Filter.RoboPreviewExclude, so previews annotated with @RoboPreviewExclude are skipped. Set it to RoboPreviewInclude to capture only previews annotated with @RoboPreviewInclude:

roborazzi {
  @OptIn(ExperimentalRoborazziApi::class)
  generateComposePreviewRobolectricTests {
    enable = true
    packages = listOf("com.example")
    annotationFilter = AnnotationFilter.Filter.RoboPreviewInclude
  }
}

To filter by your own annotations, pass their fully qualified class names (use the JVM binary name with $ for nested classes, e.g. com.example.Outer$Inner):

// Set either one, not both
annotationFilter = AnnotationFilter.Exclude("com.example.MyExcludeAnnotation")
annotationFilter = AnnotationFilter.Include("com.example.MyIncludeAnnotation")

Annotation-based Capture Control

To enable fine-grained control over screenshot timing in Compose Previews, add the new annotations dependency:

testImplementation("io.github.takahirom.roborazzi:roborazzi-annotations:[version]")

Use @RoboComposePreviewOptions to configure time-based captures:

@RoboComposePreviewOptions(
  manualClockOptions = [ManualClockOptions(advanceTimeMillis = 516L)]
)
@Preview
@Composable
fun DelayedPreview() {
  var visible by remember { mutableStateOf(false) }
  LaunchedEffect(Unit) {
    delay(500)
    visible = true
  }
  if (visible) {
    Text("Content appears after 500ms")
  }
}

This annotation enables capturing screenshots at specific time intervals, particularly useful for testing animated components or delayed state changes.

PreviewWrapper support

Previews annotated with @PreviewWrapper (Compose UI 1.11+) are automatically wrapped by ComposablePreviewScanner 0.9.0 or later, so the wrapper's content, such as a theme or background, appears in the screenshots without any extra setup:

class MyWrapperProvider : PreviewWrapperProvider {
  @Composable
  override fun Wrap(content: @Composable () -> Unit) {
    MyTheme { content() }
  }
}
@PreviewWrapper(MyWrapperProvider::class) @Preview @Composable fun WrappedPreview() { ... }

Manually adding Compose Preview screenshot tests

Roborazzi provides a helper function for ComposablePreviewScanner. You can add the following dependency to your project to use the helper function:

testImplementation("io.github.takahirom.roborazzi:roborazzi-compose-preview-scanner-support:[version]")

Then you can use the ComposablePreview<AndroidPreviewInfo>.captureRoboImage() function to capture the Composable Preview using the settings in Preview annotations. To obtain the ComposablePreview object, please refer to ComposablePreviewScanner.

fun ComposablePreview<AndroidPreviewInfo>.captureRoboImage(
  filePath: String,
  roborazziOptions: RoborazziOptions
)

The supported @Preview annotation options

Currently, we don't support all the annotation options provided by the Compose Preview. You can check the supported annotations in the source code. We are looking forward to your contributions to support more annotation options.

Experimental AI-Powered Image Assertion

Roborazzi supports AI-powered image assertion. AI-powered image assertion is an experimental feature. Screenshot tests are a great way to verify your app's UI, but verifying the content of the images can be a tedious and time-consuming task. This manual effort reduces scalability. Roborazzi can help automate this process through AI-powered image assertion, making it more efficient and scalable.

There are two new library modules: io.github.takahirom.roborazzi:roborazzi-ai-gemini and io.github.takahirom.roborazzi:roborazzi-ai-openai for AI-powered image assertion.

roborazzi-ai-gemini leverages Gemini and generative-ai-kmp, while roborazzi-ai-openai utilizes the OpenAI API through raw HTTP API calls implemented with Ktor and KotlinX Serialization

...
@get:Rule
val composeTestRule = createAndroidComposeRule<MainActivity>()
@get:Rule val roborazziRule = RoborazziRule(   options = RoborazziRule.Options(     roborazziOptions = RoborazziOptions(       compareOptions = RoborazziOptions.CompareOptions(         aiAssertionOptions = AiAssertionOptions(           aiAssertionModel = GeminiAiAssertionModel(             // DO NOT HARDCODE your API key in your code.             // This is an example passing API Key through unitTests.all{ environment(key, value) }             apiKey = System.getenv("geminiapikey") ?: ""           ),         )       )     )   ) )
@Test fun captureWithAi() {   ROBORAZZI_DEBUG = true   onView(ViewMatchers.isRoot())     .captureRoboImage(       roborazziOptions = provideRoborazziContext().options.addedAiAssertions(         AiAssertionOptions.AiAssertion(           assertionPrompt = "it should have PREVIOUS button",           requiredFulfillmentPercent = 90,         ),         AiAssertionOptions.AiAssertion(           assertionPrompt = "it should show First Fragment",           requiredFulfillmentPercent = 90,         )       )     ) }

Behavior of AI-Powered Image Assertion

AI-Powered Image Assertion runs only when the images are different. If the images are the same, AI-Powered Image Assertion is skipped. This is because AI-Powered Image Assertion can be slow and expensive.

Manual Image Assertion

You can use manual image assertion with Roborazzi. This allows you to utilize local LLMs or other LLMs. Manual Image Assertion doesn't require adding any dependencies other than Roborazzi itself.

You must provide the AiAssertionModel to RoborazziOptions to use manual image assertion.

interface AiAssertionModel {
  fun assert(
    referenceImageFilePath: String,
    comparisonImageFilePath: String,
    actualImageFilePath: String,
    aiAssertionOptions: AiAssertionOptions
  ): AiAssertionResults
}

compareOptions = RoborazziOptions.CompareOptions(
  aiAssertionOptions = AiAssertionOptions(
    aiAssertionModel = object : AiAssertionOptions.AiAssertionModel {
      override fun assert(
        comparisonImageFilePath: String,
        aiAssertionOptions: AiAssertionOptions
      ): AiAssertionResults {
        // You can use any LLMs here to create AiAssertionResults
        return AiAssertionResults(
          aiAssertionResults = aiAssertionOptions.aiAssertions.map { assertion ->
            AiAssertionResult(
              assertionPrompt = assertion.assertionPrompt,
              fulfillmentPercent = fulfillmentPercent,
              requiredFulfillmentPercent = assertion.requiredFulfillmentPercent,
              failIfNotFulfilled = assertion.failIfNotFulfilled,
              explanation = "This is a manual test.",
            )
          }
        )
      }
    },
    aiAssertions = listOf(
      AiAssertionOptions.AiAssertion(
        assertionPrompt = "it should have PREVIOUS button",
        requiredFulfillmentPercent = 90,
      ),
    ),
  )
)
          ...

Roborazzi IntelliJ IDEA and Android Studio Plugin

https://plugins.jetbrains.com/plugin/24561-roborazzi

Demo of Roborazzi IntelliJ IDEA and Android Studio Plugin.

https://github.com/takahirom/roborazzi/assets/1386930/bd3e8106-1971-4ec4-b764-3f1831999228

The Roborazzi plugin enhances your development workflow by automatically displaying screenshots related to Roborazzi's screenshot tests within IntelliJ IDEA. Easily view and verify visual outputs directly in your IDE, streamlining your testing and development process.

Multiplatform support

Experimental feature: iOS support

Roborazzi supports Compose Multiplatform iOS. You can use Roborazzi with Compose iOS as follows:

Gradle settings

plugins {
  kotlin("multiplatform")
  id("org.jetbrains.compose")
  id("io.github.takahirom.roborazzi")
}
kotlin {   sourceSets {     ...     val appleTest by getting {       dependencies {         implementation(project("io.github.takahirom.roborazzi:roborazzi-compose-ios:[1.13.0 or higher]"))         implementation(kotlin("test"))       }     }   ...

Test with Roborazzi

class IosTest {
  @OptIn(ExperimentalTestApi::class)
  @Test
  fun test() {
    runComposeUiTest {
      setContent {
        MaterialTheme {
          Column {
            Button(onClick = { }) {
              Text("Hello World")
            }
            Box(
              modifier = Modifier
                .background(Color.Red.copy(alpha = 0.5f), MaterialTheme.shapes.small)
                .size(100.dp),
            )
          }
        }
      }
      // iOS uses the same RoborazziOptions as the other targets. For example,
      // allow up to 1% of pixels to differ before a comparison fails.
      val roborazziOptions = RoborazziOptions(
        compareOptions = RoborazziOptions.CompareOptions(changeThreshold = 0.01F),
      )
      // Unlike the JVM, iOS has no automatic file-name generation, so filePath
      // is required for every capture.
      onRoot().captureRoboImage(this, filePath = "ios.png", roborazziOptions = roborazziOptions)
      onNodeWithText("Hello World").captureRoboImage(
        this,
        filePath = "ios_button.png",
        roborazziOptions = roborazziOptions,
      )
    }
  }
}

Then, you can run the Gradle tasks for iOS Support, just like you do for Android Support.

./gradlew recordRoborazzi[SourceSet]

./gradlew recordRoborazziIosSimulatorArm64
./gradlew compareRoborazziIosSimulatorArm64
./gradlew verifyRoborazziIosSimulatorArm64
...

The currently implemented features for iOS support are as follows:

| Feature | status | |---|---| | Record | supported | | Compare | supported | | Verify | supported | | Report | supported | | Dropbox/Differ comparison | supported | | threshold / resultValidator | supported | | diffPercentage | supported | | resizing image (resizeScale) | supported | | context data | supported (user-supplied only; the automatically-added default context data such as the test class name is JVM-only) | | custom reporter | supported | | ComparisonStyle | supported (Simple and Grid; Grid falls back to Simple when the density is unavailable) | | RoborazziRecordFilePathStrategy | 🆖 (filePath is required; a relative path always resolves against the output directory) | | automatic file naming | 🆖 (filePath is required) | | image format | PNG only (WebP encoding is not supported on iOS) | | pixelBitConfig | 🆖 (Rgb565 falls back to Argb8888 with a warning; CoreGraphics has no 5-6-5 format) | | dump | n/a (Robolectric-only concept) | | applyDeviceCrop | n/a (Robolectric-only concept) |

Note on translucent pixels: the iOS canvas stores pixels premultiplied (a CoreGraphics constraint), so translucent colors lose precision proportional to 255 / alpha (opaque pixels are lossless). The loss is deterministic, so comparing identically-produced images is unaffected; only cross-source comparisons of low-alpha content may need a small threshold.

iOS runs on the same shared pipeline as the JVM and Compose Desktop targets (RoborazziOptions → processOutputImageAndReport → RoboCanvas), so the image comparator, threshold / resultValidator, resizeScale, context data, custom reporters, and the reference | diff | new comparison output (including ComparisonStyle.Grid) all behave the same way. A few platform-specific features remain unsupported (see the table above); contributions are welcome.

Experimental feature: Compose Desktop support

Roborazzi supports Compose Desktop. You can use Roborazzi with Compose Desktop as follows:

Gradle settings

plugins {
  kotlin("multiplatform")
  id("org.jetbrains.compose")
  id("io.github.takahirom.roborazzi")
}
kotlin {   // You can use your source set name   jvm("desktop")   sourceSets {     ...     val desktopTest by getting {       dependencies {         implementation(project("io.github.takahirom.roborazzi:roborazzi-compose-desktop:[1.6.0-alpha-2 or higher]"))         implementation(kotlin("test"))       }     }     ...

Test target Composable function

@Composable
fun App() {
  var text by remember { mutableStateOf("Hello, World!") }
MaterialTheme {     Button(       modifier = Modifier.testTag("button"),       onClick = {         text = "Hello, Desktop!"       }) {       Text(         style = MaterialTheme.typography.h2,         text = text       )     }   } }

Test with Roborazzi

class MainKmpTest {
  @OptIn(ExperimentalTestApi::class)
  @Test
  fun test() = runDesktopComposeUiTest {
    setContent {
      App()
    }
    val roborazziOptions = RoborazziOptions(
      recordOptions = RoborazziOptions.RecordOptions(
        resizeScale = 0.5
      ),
      compareOptions = RoborazziOptions.CompareOptions(
        changeThreshold = 0F
      )
    )
    onRoot().captureRoboImage(roborazziOptions = roborazziOptions)
onNodeWithTag("button").performClick()
onRoot().captureRoboImage(roborazziOptions = roborazziOptions)   } }

Then, you can run the Gradle tasks for Desktop Support, just like you do for Android Support.

./gradlew recordRoborazzi[SourceSet]

./gradlew recordRoborazziDesktop
./gradlew compareRoborazziDesktop
./gradlew verifyRoborazziDesktop
...

If you use the Kotlin JVM plugin, the task will be recordRoborazziJvm.

The sample image

Roborazzi gradle.properties Options and Recommendations

You can configure the following options in your gradle.properties file. You can also use -P to set the options in the command line. For example, ./gradlew test -Proborazzi.test.record=true.

roborazzi.test

This option enables you to configure the behavior of Roborazzi. By default, all settings are set to false. For additional configuration options, please refer to the 'Apply Roborazzi Gradle Plugin' section.

roborazzi.test.record=true
roborazzi.test.compare=true
roborazzi.test.verify=true

roborazzi.record

roborazzi.record.resizeScale

This option lets you set the resize scale for the image being recorded. The default value is 1.0.

roborazzi.record.resizeScale=0.5

roborazzi.record.filePathStrategy

This setting allows you to specify the file path strategy for the recorded image. The default strategy is relativePathFromCurrentDirectory. If you choose relativePathFromRoborazziContextOutputDirectory, the file will be saved in the output directory specified by roborazzi.outputDir.

roborazzi.record.filePathStrategy=relativePathFromRoborazziContextOutputDirectory

roborazzi.record.namingStrategy

This option enables you to define the naming strategy for the recorded image. The default strategy is testPackageAndClassAndMethod.

• If you choose testPackageAndClassAndMethod, the file name will be com.example.MyTest.testMethod.png.
• If you choose escapedTestPackageAndClassAndMethod, the file name will be comexampleMyTest.testMethod.png.
• If you choose testClassAndMethod, the file name will be MyTest.testMethod.png.

roborazzi.record.namingStrategy=testClassAndMethod

roborazzi.cleanupOldScreenshots

This option allows you to clean up old screenshots. By default, this option is set to false. The reason why Roborazzi does not delete old screenshots by default is that Roborazzi doesn't know if you are running filtered tests or not. If you are running filtered tests, Roborazzi will delete the screenshots that are not related to the current test run.

roborazzi.cleanupOldScreenshots=true

Robolectric Options

robolectric.pixelCopyRenderMode

I recommend setting it.systemProperties["robolectric.pixelCopyRenderMode"] = "hardware" in your build.gradle file to enhance the accuracy of your screenshots. For more details, please refer to the issue.

android {
    testOptions {
    ...
        unitTests {
            isIncludeAndroidResources = true
            isReturnDefaultValues = true
            all {
                it.systemProperties["robolectric.pixelCopyRenderMode"] = "hardware"
            }

FAQ

Q: How can I run only screenshot tests using Roborazzi?

A: To run only screenshot tests, you can configure your project with the following:

android {
    testOptions {
        unitTests {
            all {
                // -Pscreenshot to filter screenshot tests
                it.useJUnit {
                    if (project.hasProperty("screenshot")) {
                        includeCategories("io.github.takahirom.roborazzi.testing.category.ScreenshotTests")
                    }
                }
            }
        }
    }
}

Include the -Pscreenshot property, and only the screenshot tests will be run.

Note: This feature is not provided in the Roborazzi library itself, to keep it simple and utilize JUnit's built-in features for test filtering.

You can also annotate your tests like this:

/**
 * You can filter ScreenshotTests using -Pscreenshot parameter
 */
interface ScreenshotTests
@Test @Category(ScreenshotTests::class) fun checkLaunchShot() {   onRoot().captureRoboImage(roborazziOptions = roborazziOptions) }

This allows you to create a category of screenshot tests and filter them using the -Pscreenshot property, thus making it easier to run only those specific tests.

Q: How can I debug screenshot tests in Android Studio?

Q: How can I execute screenshot tests using Android Studio's Run button?

A: To execute screenshot tests using Android Studio's Run button, configure your project as follows:

gradle.properties

roborazzi.test.record=true

After that, you can execute screenshot tests using either Android Studio's Run or Debug button as you normally would.

Q: My screenshot tests are not capturing images. What could be the issue?

A: If your screenshot tests are not capturing images, there may be several patterns that are causing this issue. Please follow these troubleshooting steps:

• Enable Debugging: Set ROBORAZZI_DEBUG = true to see logs.
• Check Plugin: Ensure that the plugin is properly applied.
• Run Task: Verify that the recordRoborazziDebug task is running.
• Call Method: Confirm that captureRoboImage() is being called.

Q: I'm seeing an optimization warning related to Java lambdas in Gradle. What can I do?

A: This warning may occur with Gradle 7.5. Upgrade to Gradle 7.6.2 to resolve this issue. Change the distribution URL in gradle-wrapper.properties:

distributionUrl=https\://services.gradle.org/distributions/gradle-7.6.2-bin.zip

Q: Can I run Roborazzi with Bazel?

A: As of now, there is no direct support for running Roborazzi with Bazel. However, it is possible to do so. Please refer to the following comment for more details: Roborazzi Bazel Support Comment

Q: My tests are being skipped or, conversely, are being run when they should be skipped. How can I handle caching to address this?

A: The behavior you are experiencing may be related to caching issues. Although it's experimental, you can set the outputDir parameter in your build.gradle file to handle caching and improve the stability of your tests. This parameter allows you to specify the output directory for your screenshots, which can help in managing the cache. Here is how you can set it up: If you use the default output directory(module/build/outputs/roborazzi), specifying the outputDir parameter is not necessary. For more reference, you can check out the issue.

roborazzi {
    outputDir = "src/your/screenshot/folder"
}

If the caching problems appear when several Roborazzi test tasks run in a single Gradle invocation (for example check or Kotlin Multiplatform's allTests), the tasks may be racing over the shared output directory. In that case you can enable the experimental separateOutputDirs option so each variant/target gets its own directory. See Separate output directories per variant/target.

Q: Why do my screenshot tests fail inconsistently across different operating systems like MacOS, Ubuntu, and Windows?

A: This is a known issue caused by variations in how graphics libraries render components on different platforms. This issue is due to variations in how graphics libraries render components on different platforms. As we've seen with Now in Android, there are no guarantees for identical rendering across all environments. To ensure more consistent results, consider configuring your continuous integration (CI) environment to both record and test screenshots. This setup minimizes discrepancies by using the same settings and resources for all tests.

Q: The images taken from Roborazzi seem broken

A: First, please check if you are using the correct version of the Android SDK. Consider using API level 28 or higher because it seems that Robolectric Native Graphics doesn't work property on older SDK versions.

You can specify the SDK version like @Config(sdk = [33]) or by using robolectric.properties with sdk=33. https://robolectric.org/configuring/

If your images are mostly fine but there are some drawing issues like shadows or shape graphics, you can try using Robolectric's Hardware Rendering mode. Please refer to this issue.

Q: I am seeing Out Of Memory errors.

A: You may solve this by using unitTests.maxHeapSize to adjust the unit test heap size as follows:

android {   ...   testOptions {     unitTests.all {       maxHeapSize = "4096m"     }   } }

Q: [IDEA Plugin] Roborazzi Gradle task is not displayed in Tool Window.

A: It is discussed in this issue. To enable the display of Roborazzi tasks, please enable Configure all Gradle tasks during Gradle Sync (this can make Gradle Sync slower) in the Settings | Experimental | Gradle.

LICENSE

``` Copyright 2023 takahirom Copyright 2019 Square, Inc. Copyright The Android Open Source Project

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in com