I'm talking about easy stuff, too, like normal flow, margin, border, padding box alignment.

The existing official test suites are entirely manual.

Edit: What you're describing requires you to make the entire world first, then finally test something.

Here's an example: I want to test the white-space property. How do I test that? Oh also, font rasterizers are all different and standards don't dictate what happens after box layout. It's acceptable that glyphs render with different dimensions.

How do I test that? A casual HN reader isn't going to care. Someone actually writing this stuff, will.