> Fail	background-color: rgba(5, 7, 10, 0.5)	assert_equals: background-color raw inline style declaration expected "rgba(5, 7, 10, 0.5)" but got "rgba(5, 7, 10, 0.498039)"

This is  issue 453414 .

> Fail	clip: rect(1em, auto, 0.5px, 2000em)	assert_equals: clip raw inline style declaration expected "rect(1em, auto, 0.5px, 2000em)" but got "rect(1em auto 0.5px 2000em)"

rect() should serialize with commas.
"Append the result of invoking serialize a comma-separated list on list to s."
https://drafts.csswg.org/cssom/#serialize-a-css-component-value

> Fail	content: counter(par-num)	assert_equals: content raw inline style declaration expected "counter(par-num, decimal)" but got "counter(par-num)"

This... is either a bug in the spec or a bug in the test. :-|

"Let list be a list of CSS component values belonging to <counter>, omitting the last CSS component value if it is "decimal"."
https://drafts.csswg.org/cssom/#serialize-a-css-component-value

Filed spec issue https://github.com/w3c/csswg-drafts/issues/670

> Fail	font-variant: normal	assert_equals: font-variant raw inline style declaration expected "normal" but got ""
> Fail	outline-color: invert	assert_equals: outline-color raw inline style declaration expected "invert" but got ""
> (more similar failures)

Not sure what's up with these.