[filter-sign-function.html]
  [contrast(calc(sign(1em - 1px) * 2)) should be used-value-equivalent to contrast(2)]
    expected: FAIL

  [contrast(calc(sign(1em - 1px) * 2%)) should be used-value-equivalent to contrast(2%)]
    expected: FAIL

  [hue-rotate(calc(sign(1em - 1px) * 2deg)) should be used-value-equivalent to hue-rotate(2deg)]
    expected: FAIL