[css-typed-om] Is using a constructed expression of the form 1px/1px invalid as a <number>

[weinig]

The WPT test css/css-typed-om/stylevalue-subclasses/cssScale.tentative.html requires that the following throw an exception:

let coord = new CSSMathProduct(CSS.px(1), new CSSMathInvert(CSS.px(1)));
let scale = new CSSScale(coord, 0);

with a description calling the product "an invalid division by px/px".

I can't find where (or if) this is required by the current CSS Typed OM draft (and it may just be an invalid test, it is marked tentative), but may be missing it.

Should this be invalid?

[xiaochengh]

The test seems wrong. The spec allows px/px.

@DevSDK

[tabatkins]

Yeah, that is explicitly allowed behavior. The test is wrong.

[DevSDK]

@xiaochengh @weinig @tabatkins Yeah. The sepc says it is allowed.
Specifically, it was Chromium behaviour (probably still is). I missed that should not be external WPT test at here.
I'll fix WPT later :)

[weinig]

I took care of updating the test with web-platform-tests/wpt#47897.