Test assert text: When 'text-orientation' is 'upright', then the dominant baseline is still vertical, and since the baseline is vertical, then the definitions for 'mixed' (or 'sideways') still apply; i.e., line-over is on right, and line-under is on left. So, here, in this test, the filled-in circles ('text-emphasis') should be positioned on the righthand side of each of the 3 orange stripes. Firefox 50+ and Chrome 50+ position all 3 filled-in circles on the middle right of orange stripes (strictly compliant with what the current specification states). Safari 9.1+ incorrectly positions all 3 filled-in circles on the middle top of orange stripes. 2017-02-16
More info: Re: [css-text-decor] Proposal for the 'text-emphasis-position' property syntax values