Is there an online tool to pretty print the

data class

toString()

output? I have a lot of nested data classes and when a test fails it's quite cumbersome to compare the linear outputs of the standard

toString()

implementation of a data class.

Did you try to compare within IntelliJ? AFAIR you can enable soft wraps and see a nice diff

Yes, I have soft wraps activated and I compare in IntelliJ, but it looks like this:

org.opentest4j.AssertionFailedError: 
expected: SensorAutomationScreenState(isEditMode=false, name=, connectorsWithSensors=[ConnectorWithSensors(connectorInfo=Connector(id=controlDeviceConnectorId1, name=controlDeviceConnectorName1, productType=AIR), sensors=[ItemSelection(id=controlDeviceId1, name=controlDeviceName1, selected=true, enabled=true), ItemSelection(id=controlDeviceId2, name=controlDeviceName2, selected=true, enabled=true)]), ConnectorWithSensors(connectorInfo=Connector(id=controlDeviceConnectorId2, name=controlDeviceConnectorName2, productType=AIR), sensors=[ItemSelection(id=controlDeviceId3, name=controlDeviceName3, selected=false, enabled=true)])], time=ANYTIME, scenes=Scenes(supportedScenes=[ItemSelection(id=sceneId2, name=sceneName2, selected=false, enabled=true)], unsupportedScenes=[ItemSelection(id=sceneId1, name=sceneName1, selected=false, enabled=false), ItemSelection(id=sceneId3, name=sceneName3, selected=false, enabled=true), ItemSelection(id=sceneId4, name=sceneName4, selected=false, enabled=false)]), noMotionScenes=Scenes(supportedScenes=[ItemSelection(id=sceneId2, name=sceneName2, selected=false, enabled=true)], unsupportedScenes=[ItemSelection(id=sceneId1, name=sceneName1, selected=false, enabled=false), ItemSelection(id=sceneId3, name=sceneName3, selected=false, enabled=true), ItemSelection(id=sceneId4, name=sceneName4, selected=false, enabled=false)]), noMotionDelay=5, isSaveButtonEnabled=false, showDeleteButton=false, showConfirmDeleteAutomationDialog=false, location=null, showNotSupportedScenes=false, showNotSupportedNoMotionScenes=false, sceneNotSupportedDialogState=SceneNotSupportedDialogState(show=false, sceneNames=))
 but was: SensorAutomationScreenState(isEditMode=false, name=, connectorsWithSensors=[ConnectorWithSensors(connectorInfo=Connector(id=controlDeviceConnectorId1, name=controlDeviceConnectorName1, productType=AIR), sensors=[ItemSelection(id=controlDeviceId1, name=controlDeviceName1, selected=true, enabled=true), ItemSelection(id=controlDeviceId2, name=controlDeviceName2, selected=true, enabled=true)]), ConnectorWithSensors(connectorInfo=Connector(id=controlDeviceConnectorId2, name=controlDeviceConnectorName2, productType=AIR), sensors=[ItemSelection(id=controlDeviceId3, name=controlDeviceName3, selected=false, enabled=false)])], time=ANYTIME, scenes=Scenes(supportedScenes=[ItemSelection(id=sceneId2, name=sceneName2, selected=false, enabled=true)], unsupportedScenes=[ItemSelection(id=sceneId1, name=sceneName1, selected=false, enabled=false), ItemSelection(id=sceneId3, name=sceneName3, selected=false, enabled=false), ItemSelection(id=sceneId4, name=sceneName4, selected=false, enabled=false)]), noMotionScenes=Scenes(supportedScenes=[ItemSelection(id=sceneId2, name=sceneName2, selected=false, enabled=true)], unsupportedScenes=[ItemSelection(id=sceneId1, name=sceneName1, selected=false, enabled=false), ItemSelection(id=sceneId3, name=sceneName3, selected=false, enabled=false), ItemSelection(id=sceneId4, name=sceneName4, selected=false, enabled=false)]), noMotionDelay=5, isSaveButtonEnabled=false, showDeleteButton=false, showConfirmDeleteAutomationDialog=false, location=null, showNotSupportedScenes=false, showNotSupportedNoMotionScenes=false, sceneNotSupportedDialogState=SceneNotSupportedDialogState(show=false, sceneNames=))

I get this in IDEA:

I use AssertJ

You could also try https://github.com/bnorm/kotlin-power-assert or (if your classes can be made

@Serializable

for kotlinx.serialization) serialize them with

Json { prettyPrint = true }

and use the result for printing.

Sometimes in the test failure message you have a "compare" link that opens this kind of comparison window. However, I don't always see it, and I haven't figured out in which case I get it. It might depend on the assertion library.

@Joffrey yes and no. The exceptions have to be of a certain subtype for the compare link to appear, but usually assertion libraries should match that criteria. The most often cause is, that you delegeat test execution to Gradle where the compare tool integration is broken as the exceptions get changed on the fly unfortunately. If you use the IntelliJ test runner, the compare tool integration works, but you might miss important configuration for the test task in the build script. https://youtrack.jetbrains.com/issue/IDEA-221624/No-diff-tool-integration-when-delegating-tests-to-Gradle

@Vampire oh thanks! Now I finally know why (somehow I didn't care enough to Google it for long 😅). Yeah I usually set up IDEA to run tests using Gradle in order to match the actual configuration, and not have surprises on the CI