paparazzi VS vizzy

Component API tests are written for all components in the library. These are Paparazzi snapshot tests that are parameterized to cover all the combinations of values for the properties in the API of a given component. Additionally, they include as parameters: color theme, layout direction, and optionally other properties that may be relevant to the component under test (e.g., font scale).

Looks really nice. Sadly, I wasn't able to test it because it doesn't support application module

Curious what you mean by hilt refuses to work and what you have tried? Usually though if I'm testing the UI of the app, I might use paparazzi for screenshot tests because it doesn't have to run the test on device. Then for a UI integration test for navigation and user flows, use espresso and replace the network data sources with mocks which in your case would be with hilt android test rule and test install in annotation .

/** * Finds all files in the components module which have Compose previews * and generates Paparazzi screenshot tests for them. * * The generated tests can then be used to record screenshots with * ./gradlew components:recordPaparazziInternalDebug * * To verify that the current implementation matches the recorded screenshots * ./gradlew components:verifyPaparazziInternalDebug */ fun main() { val path = System.getProperty("user.dir") ?: error("Can't get user dir") // Paparazzi does not currently work in the app module: https://github.com/cashapp/paparazzi/issues/107 // For now this is hardcoded to only check files in the components module. // If we pull our compose files out of the app module to a separate module this code has to be updated. File(path).walk().filter { it.path.contains("/components/src/main/java") && it.extension == "kt" }.forEach { if (it.readText().contains("@Preview")) { processFileWithPreviews(it) } } } /** * Reads the given file, finds the names of all the functions annotated with @Preview * and uses them to generate a Paparazzi test file with one test for each preview. */ private fun processFileWithPreviews(file: File) { val lines = file.readLines() val previewNames = mutableListOf() var saveNextFunctionName = false var packageName = "" lines.forEachIndexed { i, line -> if (i == 0) { packageName = line.split(" ").last() } if (line.contains("@Preview")) { saveNextFunctionName = true } if (saveNextFunctionName && line.startsWith("fun ")) { previewNames += line.split(" ")[1].removeSuffix("()") saveNextFunctionName = false } } val pathString = file.path.replace("src/main", "src/test").split("java").first() + "java" val testFilePath = pathString.toPath() generatePaparazziTest(packageName, file.nameWithoutExtension + "PaparazziTest", testFilePath, previewNames) } fun generatePaparazziTest(packageName: String, fileName: String, path: Path, previewNames: List) { val classBuilder = TypeSpec.classBuilder(fileName) .superclass(PaparazziTest::class) .addAnnotation( AnnotationSpec.builder(Suppress::class) // KotlinPoet does not let us remove redundant public modifiers or Unit return types for the functions, // but we don't mind for generated code as long as the tests work .addMember("\"RedundantVisibilityModifier\", \"RedundantUnitReturnType\"") .build() ) previewNames.forEach { classBuilder.addFunction( FunSpec.builder(it.removeSuffix("Preview").usLocaleDecapitalize()) .addStatement("paparazziRule.snapshot { $it() }") .addAnnotation(Test::class) .build() ) } val testFile = FileSpec.builder(packageName, fileName) .addType(classBuilder.build()) .addFileComment("AUTO-GENERATED FILE by generate_paparazzi_tests.kt\nDO NOT MODIFY") .build() val nioPath = path.toNioPath() testFile.writeTo(nioPath) }

The good thing is, Square got us covered once more, in regards to the flaky emulators, by providing a screenshot-testing library that does not require an emulator: https://cashapp.github.io/paparazzi/

You can avoid having to do the step of recording screenshots if you use a tool like Screenshotbot (https://github.com/screenshotbot/screenshotbot-oss) or Vizzy (https://github.com/workday/vizzy)

There are open source tools to achieve this workflow. I've personally built screenshotbot (https://screenshotbot.io / https://github.com/screenshotbot/screenshotbot-oss), I've also built the screenshot testing infrastructure at Facebook. Workday has open-sourced their own tool at https://github.com/workday/vizzy. AirBnb uses another commercial tool called Happo (https://happo.io). Use any of these services with Paparazzi.

There are a few open source tools to do this: there's a tool I built: https://github.com/screenshotbot/screenshotbot-oss similar to the infrastructure at Facebook, and there's another one built at Workday: https://github.com/workday/vizzy. These are screenshot-library agnostic services to notify you on Pull Requests when screenshots change.