actually the LineStyle property is *write-only*

... which is highly suspect in any case, but whatever.

Change-Id: Ibeff36a7d30750fc33e9729b067f86b3901d1c76
sw: when getting a property value in a unit test, a void result is a bug

Change-Id: Iba0e43c198c3380426d0572427c591f4d77ba09b