That is not possible in GIMP. The only tool you get for that get is to use Layer->Transform->Offset... so that what are your edges become your image center and vice-versa.
To visualize how the pattern is going you need to have another, large, image open, copy the image being edited to the clipboard (Edit->Copy Visible if it is a multi-layer work), then select the Pattern dialog (Windows->Dockable Dialogs->Pattern): your work will be shown as the first pattern on that dialog, as that reflects the contents of the clipboard - switch to the larger image and drag that first pattern to the canvas: t will be used to fill the image.
So, it is not live, but there is a possible workflow.