Valid to use subproperties as reference file for shorthand property test?

Hi,

My colleague (CC'ed) is trying to create some reference files to automate CSS tests.

After reading a test at

https://github.com/w3c/csswg-test/blob/master/css21/fonts/font-044.xht

... that "a system font sets all of the font subproperties at the same time; then each font subproperty can be altered individually",
... he creates a reference file at

https://github.com/chenxix/csswg-test/blob/473dafa9a5420cd7e0ee583789a7d109109d0ca6/css21/fonts/font-003-ref.html
span {
  font-variant: small-caps;
  font-size: 1in;
  font-family: serif;
  line-height: 1em;
}

... for the test case at
https://github.com/chenxix/csswg-test/blob/473dafa9a5420cd7e0ee583789a7d109109d0ca6/css21/fonts/font-003.xht
span
{
  font: small-caps 1in serif;
  line-height: 1em;
}

Is this a valid method to create reference file?

Per http://testthewebforward.org/docs/reftests.html#2-the-reftest-reference-file, "reference file must not use the same features that are being tested, but uses a different method to produce the same rendering as a test file", seems this method is not acceptable.

Feel free to review the reference files at
https://github.com/w3c/csswg-test/pull/604

Thanks,
Zhiqiang