Fix location url resolution.

src/001-xml_http_request.coffee

@@ -501,7 +501,7 @@ class XMLHttpRequest extends XMLHttpRequestEventTarget
     # Transparent redirection handling.
     switch response.statusCode
       when 301, 302, 303, 307, 308
-        @_url = @_parseUrl response.headers['location']
+        @_url = @_parseUrl (url.resolve @_url['href'], response.headers['location'])
         @_method = 'GET'
         if 'content-type' of @_loweredHeaders
           delete @_headers[@_loweredHeaders['content-type']]

test/src/helpers/xhr_server.coffee

@@ -119,8 +119,11 @@ class XhrServer
     # Returns a HTTP redirect. Used to test the redirection handling code.
     @app.all '/_/redirect/:status/:next_page', (request, response) =>
       response.statusCode = parseInt(request.params.status)
-      response.header 'Location',
-          "http://#{request.get('host')}/_/#{request.params.next_page}"
+      if request.query.relative
+        url = "/#{request.params.next_page}"
+      else
+        url = "http://#{request.get('host')}/_/#{request.params.next_page}"
+      response.header 'Location', url
       body = "<p>This is supposed to have a redirect link</p>"
       response.header 'Content-Type', 'text/html'
       response.header 'Content-Length', body.length.toString()

test/src/redirect_test.coffee

@@ -19,6 +19,13 @@ describe 'XMLHttpRequest', ->
         done()
       @xhr.send()
 
+    it 'resolves effective request uri for the next location', (done) ->
+      @xhr.open 'GET', 'http://localhost:8912/_/redirect/302/method?relative=true'
+      @xhr.onload = =>
+        expect(@xhr._url['href']).to.match(/http:\/\/localhost:8912\/method/)
+        done()
+      @xhr.send()
+
     it 'persists custom request headers across redirects', (done) ->
       @xhr.open 'GET', 'http://localhost:8912/_/redirect/302/headers'
       @xhr.setRequestHeader 'X-Redirect-Test', 'should be preserved'