more tests done on graphical matrix operations.

Change-Id: I11f3ad6bcf1010a892e708d3b33aea8827f5e266
Reviewed-on: http://www.matthewh.me/gerrit/9
Reviewed-by: Matthew Hoggan <matthew.hoggan@matthewh.me>
Tested-by: Matthew Hoggan <matthew.hoggan@matthewh.me>