test.robot.javafx.scene.layout.RegionBackgroundFillUITest logs following exceptions :

test.robot.javafx.scene.layout.RegionBackgroundFillUITest > basicFill_NegativeRadius1 STANDARD_ERROR
    Jan 30, 2018 5:25:29 PM javafx.scene.CssStyleHelper calculateValue
    WARNING: Caught java.lang.IllegalArgumentException: No radii value may be < 0' while calculating value for '-fx-background-radius' from inline style on Region@4b86edfd

test.robot.javafx.scene.layout.RegionBackgroundFillUITest > basicFill_NegativeRadius2 STANDARD_ERROR
    Jan 30, 2018 5:25:33 PM javafx.scene.CssStyleHelper calculateValue
    WARNING: Caught java.lang.IllegalArgumentException: No radii value may be < 0' while calculating value for '-fx-background-radius' from inline style on Region@4a2de7c5

test.robot.javafx.scene.layout.RegionBackgroundFillUITest > basicFill_NegativeRadius3 STANDARD_ERROR
    Jan 30, 2018 5:25:37 PM javafx.scene.CssStyleHelper calculateValue
    WARNING: Caught java.lang.IllegalArgumentException: No radii value may be < 0' while calculating value for '-fx-background-radius' from inline style on Region@4e699c2a

test.robot.javafx.scene.layout.RegionBackgroundFillUITest > basicFill_NegativeRadius4 STANDARD_ERROR
    Jan 30, 2018 5:25:41 PM javafx.scene.CssStyleHelper calculateValue
    WARNING: Caught java.lang.IllegalArgumentException: No radii value may be < 0' while calculating value for '-fx-background-radius' from inline style on Region@53ac7e48

Action Needed :
-----------------------
Evaluate validity of these exceptions and correct the tests/code if found to be invalid.