Data Integration is becoming more and more complex as customer requirements and expectations are continuously changing. There is increasingly a need among users to develop and debug their Extract Transform/Load (ETL) and Extract Load/Transform (ELT) workflows iteratively. Now, Azure Data Factory (ADF) visual tools allow you to do iterative development and debugging.
You can create your pipelines and do test runs using the Debug capability in the pipeline canvas without writing a single line of code. You can view the results of your test runs in the Output window of your pipeline canvas. Once your test run succeeds, you can add more activities to your pipeline and continue debugging in an iterative manner. You can also Cancel your test runs once they are in-progress. You are not required to publish your changes to the data factory service before clicking Debug. This is helpful in scenarios where you want to make sure that the new additions or changes work as expected before you update your data factory workflows in dev, test or prod environments.
Read about it in the Azure blog.