[flex-shorthand-calc.html]
  [e.style['flex'\] = "sign(1em - 1px) sibling-index()" should set flex-basis]
    expected: FAIL

  [e.style['flex'\] = "sign(1em - 1px) sibling-index()" should set flex-grow]
    expected: FAIL

  [e.style['flex'\] = "sign(1em - 1px) sibling-index()" should set flex-shrink]
    expected: FAIL

  [e.style['flex'\] = "sign(1em - 1px) sibling-index()" should not set unrelated longhands]
    expected: FAIL