Normalize CSS colors for IE6-8

[JamesMGreene]

TL;DR: This addon currently does not normalize certain CSS style properties (e.g. color values) in IE < 9.

IE9+ and other browsers normalize the value the user sets. IE8- leaves the value as exactly what the user specified, even if error correction behavior handles it differently. For a little more info, see qunitjs/qunit#368.

Implementation notes for fixing:

• http://www.sophox.com/wordpress/?p=833
• http://www.sophox.com/wordpress/?p=882
• http://stackoverflow.com/questions/11839088/get-real-value-of-a-css-color-property-in-script
• http://blog.stchur.com/2006/06/21/css-computed-style/
• http://msdn.microsoft.com/en-us/library/ie/ms535231(v=vs.85).aspx

[JamesMGreene]

e.g. for { "color": "red" }

"red" === "#FF0000" === "#F00" === "#FF0000FF" === "rgb(255, 0, 0)"

[JamesMGreene]

More Notes:

• There are currently 148 named colors: http://dev.w3.org/csswg/css-color/#named-colors

• There are also a few special keywords like transparent (rgb(0, 0, 0, 0)) and currentcolor (weird).

• Newer browsers also support new color functions like hsl, hsla, rgba, device-cmyk, etc.:

  <color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> |
            <hwb()> | <gray()> | <device-cmyk()> | <color()> |
            <hex-color> | <named-color> | currentcolor | transparent
  

[JamesMGreene]

Suggestion: I am thinking any work on this should be implemented as an optional "module" that can be optionally included (namely just for IE<9, I guess), e.g.

QUnit.assert.html.color = function normalizeColor(val, prop, el) {
  /* Normalize color values here */
  /* `el` and `prop` would be needed to support `currentcolor`, otherwise they are unnecessary */
};