These should all pass:
@supports (color: green): PASS
@supports (color: green) and (width: 50px): PASS
@supports (color: green) or (flogwizzle: purple): PASS
@supports (not (flogwizzle: purple)): PASS
@supports selector(.simple): PASS
@supports selector(a#more > .complicated.case:nth-child(42)): PASS
@supports selector(.easy) or selector(.....nope): PASS

These should all fail:
@supports (not (color: green)): FAIL
@supports (color: green) and (width: 50px) or (color: green): FAIL
@supports (width: yellow) or (height: green): FAIL
@supports (flogwizzle: purple): FAIL
@supports selector(.....nope): FAIL
@supports selector(::-webkit-input-placeholder): FAIL
@supports selector(32) or selector(thing[foo??????bar]): FAIL