fallbacks", "flip-block, flip-inline flip-inline");
  test_invalid_value("position-try-fallbacks", "--bar flip-block --foo");
  test_invalid_value("position-try-fallbacks", "--foo --bar");
  test_invalid_value("position-try-fallbacks", "flip-inline --bar flip-block");
  test_invalid_value("position-try-fallbacks", "-foo");
  test_invalid_value("position-try-fallbacks", "foo");
  test_invalid_value("position-try-fallbacks", "flip-start 123");
  test_invalid_value("position-try-fallbacks", "--foo 123");
  tes