1. Go to Tests section, click over the dotted icon next to the desired folder.
2. Drag the folder and drop it where you need to. If you want to move it as parent folder, drop it closer to the left edge of the screen.
3. Your folder has been moved as parent.
4. Optional: If you want to move it as child folder, drop it a little bit to the right, below the desired parent folder.
5. Your folder has been moved as child.