Per spec, at least. I'm not changing this code for the moment in bug 745897.
Thanks! The test does catch it. Also filed bug 753734 about Firefox's intolerable slowness at generating JS warnings, which shows here when the webgl.verbose preference is set to true.
The JS warning slowness no longer affects WebGL warnings too much, as we now stop generating WebGL warnings after 32 per context.
Created attachment 628314 [details] [diff] [review] reject bad enum