This tests to make sure that baseVal and animVal are tied when animation is not enabled:
svg.x.baseVal.value = 0
svg.x.animVal.value = 0
setting svg.x.baseVal.value = 10
svg.x.baseVal.value = 10
svg.x.animVal.value = 10
SUCCESS (1 of 2)
setting svg.x.animVal.value = 5
caught exception: Failed to set the 'value' property on 'SVGLength': This object is read-only.
svg.x.baseVal.value = 10
svg.x.animVal.value = 10
SUCCESS (2 of 2)