I have moved my dataset file from the Development workspace to the Test workspace for the very first time. Assuming I have two years of data in the Development workspace, how much data will be there in the Test workspace for the first time before refresh?

When you move a dataset from the Development workspace to the Test workspace using a deployment pipeline, only the metadata is copied to the Test workspace. This means that the Test workspace will not contain any data until it is refreshed.

Data is not transferred from the source workspace to the target workspace during the deployment process. All deployments are metadata-only, so a data refresh is required after deploying to the target workspace. For initial deployments, you will also need to configure the data source credentials or gateway connectivity as necessary.

File after the first deployment. No Data