    GET http://localhost:8000/assert-header

    HTTP 200
    Content-Type: text/html; charset=utf-8
    Set-Cookie: cookie1=value1; Path=/
    Set-Cookie: cookie2=value2; Path=/
    [Asserts]
    header "Custom" not exists
    header "Content-Type" exists
    header "Header1" == "value1"
    header "ETag" == "\"33a64df551425fcc55e4d42a148795d9f25f89d4\""
    header "Set-Cookie" exists
    header "Set-Cookie" count == 3
    header "Set-Cookie" includes "cookie1=value1; Path=/"
    header "Set-Cookie" not includes "cookie4=value4; Path=/"