When I pass HTTP headers like "Accept" or "If-Not-Modifed-Since" to a get request in a Rails integration test, the test base class prefixes the headers with "HTTP-", and converts them to upper case.
Why does it prepend "HTTP-"? I looked over the spec at W3C, and there is no mention of such a prefix. My browser sends "If-Not-Modified- Since", without a prefix.