Cookie duplication using request.addCookie

[roman0x58]

Hi, I'm facing an issue, when adding a cookie with the same name, it results the cookie being presented in request.cookies twice.

The test will fail with List(someCookieName=foo, someCookieName=bar) did not equal List (someCookieName=bar)

val request: Request[IO] = Request()
    .addCookie(RequestCookie("someCookieName", "foo"))
    .addCookie(RequestCookie("someCookieName", "bar"))

request.cookies must equal (RequestCookie("someCookieName", "bar") :: Nil)

If this is the intended behavior, it would be great to have something like replaceCookie or so.

[danicheg]

I failed to find references in the spec that the Cookie header must contain only unique keys. However, this might be considered a natural behaviour. Given that, I'd suggest modifying the existing Cookie header in the Request via org.http4s.Message#transformHeaders, org.http4s.Message#removeHeader and org.http4s.Message#addHeader.