Dates in preferred format:
    input:
        head:
            Date: 'Thu, 05 Mar 2020 23:08:55 GMT'
            Expires: 'Wed, 11 Mar 2020 09:22:00 GMT'
            Last-Modified: 'Tue, 03 Mar 2020 06:14:00 GMT'
    output:
        meta:
            date: '2020-03-05T23:08:55Z'
            expires: '2020-03-11T09:22:00Z'
            lastModified: '2020-03-03T06:14:00Z'

Dates in RFC 850 format:
    input:
        head:
            Date: 'Thursday, 05-Mar-20 23:08:55 GMT'
            Expires: 'Wednesday, 11-Mar-20 09:22:00 GMT'
            Last-Modified: 'Tuesday, 03-Mar-20 06:14:00 GMT'
    output:
        meta:
            date: '2020-03-05T23:08:55Z'
            expires: '2020-03-11T09:22:00Z'
            lastModified: '2020-03-03T06:14:00Z'
            
Dates in asctime() format:
    input:
        head:
            Date: 'Thu Mar  5 23:08:55 2020'
            Expires: 'Wed Mar 11 09:22:00 2020'
            Last-Modified: 'Tue Mar  3 06:14:00 2020'
    output:
        meta:
            date: '2020-03-05T23:08:55Z'
            expires: '2020-03-11T09:22:00Z'
            lastModified: '2020-03-03T06:14:00Z'

Invalid dates:
    input:
        head:
            Date: 
                - 'Thu, 05 Mar 2020 25:08:55 GMT' # impossible time
                - 'Fri, 06 Mar 2020 09:22:00 EST' # bad timezone
                - 'Wed, 03 Mar 2020 06:14:00 GMT' # wrong weekday
                - 'Tue Mar 3 06:14:00 2020'       # missing padding before single-digit day of month
                - 'thu, 05 Mar 2020 23:08:55 GMT' # bad casing
    output:
        meta: {}

Content type:
    input:
        head:
            Content-Type: 'application/atom+xml'
    output:
        meta:
            type: 'application/atom+xml'

Invalid content type:
    input:
        head:
            Content-Type: 'application/atom/xml'
    output:
        meta: {}

ETag:
    input:
        head:
            ETag: '"jwhwh"'
    output:
        meta:
            etag: '"jwhwh"'

Age:
    input:
        head:
            Age: '012345'
    output:
        meta:
            age: 'PT12345S'

Max age 1:
    input:
        head:
            Cache-Control: 'max-age=123'
    output:
        meta:
            maxAge: 'PT123S'

Max age 2:
    input:
        head:
            Cache-Control: 'max-age="123"'
    output:
        meta:
            maxAge: 'PT123S'

Max age 3:
    input:
        head:
            Cache-Control: 'max-age="001\23"blah'
    output:
        meta:
            maxAge: 'PT123S'

Max age 4:
    input:
        head:
            Cache-Control: 's-maxage=123, s-maxage=22'
    output:
        meta:
            maxAge: 'PT123S'

Max age 5:
    input:
        head:
            Cache-Control: 
               - 'no-store, max-age=123'
               - 'must-revalidate'
               - 's-maxage=22'
    output:
        meta:
            maxAge: 'PT22S'

Links:
    doc_url: 'http://example.org/blah'
    input:
        head:
            Link: '<http://example.com/>; rel="alternate"; type="appplication/atom+xml; charset=\"UTF-8\";", </>; rel=alternate; type="application/rss+xml"'
    output:
        meta:
            url: 'http://example.org/blah'
            links:
                - url: 'http://example.com/'
                  anchor: 'http://example.org/blah'
                  rel: alternate
                  type: 'appplication/atom+xml;charset=UTF-8'
                - url: ['/', 'http://example.org/blah']
                  anchor: 'http://example.org/blah'
                  rel: alternate
                  type: 'application/rss+xml'