Workflow Testing: Re-use previous start variables values

Currently, in workflow testing, we have to input all start variable values over again when running a new instance. This can be extremely time-consuming in testing.
It would be great if we could re-populate previous values when using the workflow testing interface in the workflow designer.

Use case:
In the Upgrade Center, we often get workflows for clients that are component or site workflows that require various start variable inputs to run/pass and even to build up other variables within the workflow. We cannot get these values in the workflows as they are not tied to any list in SharePoint etc.
This results in needing to re-input these values each time a new instance/test is run. Having the ability to re-add previous test values would speed up dev testing time considerably