How to do an automated UI test on a diagramming WPF application

Assume i have a WPF diagramming application like this example: https://www.codeproject.com/Articles/24681/WPF-Diagram-Designer-Part-4

• How can I do an automated UI test for functions like:
• Inserting a new item per drag and drop
• Connecting 2 items
• Deleting an item

I seen test libraries like "White" or "Appium" which is good for some text input but I have no glue how to do for example drag and drop of items in an automated test.