testExtendFront :: (Int, Array U DIM1 Double, Array U DIM1 Double)
              -> Assertion
testExtendFront (ln, sig, expected) =
    expected @=~? forceS (extendFront ln sig)
testExtendFront :: (Int, Array U DIM1 Double, Array U DIM1 Double)
              -> Assertion
testExtendFront (ln, sig, expected) =
    expected @=~? forceS (extendFront ln sig)
testExtendFront (ln, sig, expected) =
    expected @=~? forceS (extendFront ln sig)