Add support for Extended MKCOL (RFC5689)

spec/support/examples/ext_mkcol.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: false
+
+module Support
+  module Examples
+    module ExtMkcol
+      # RFC5689: 3.4. Successful Extended MKCOL Request
+      def self.rfc5689_3_4
+        <<~XML
+          <?xml version="1.0" encoding="utf-8" ?>
+          <D:mkcol xmlns:D="DAV:"
+                        xmlns:E="http://example.com/ns/">
+            <D:set>
+              <D:prop>
+                <D:resourcetype>
+                  <D:collection/>
+                  <E:special-resource/>
+                </D:resourcetype>
+                <D:displayname>Special Resource</D:displayname>
+              </D:prop>
+            </D:set>
+          </D:mkcol>
+XML
+      end
+    end
+  end
+end

spec/support/request_helpers.rb

@@ -1,7 +1,7 @@
 module ActionDispatch
   module Integration
     module RequestHelpers
-      %w[copy move mkcol propfind proppatch lock unlock].each do |method|
+      %w[copy move mkcol options propfind proppatch lock unlock].each do |method|
         define_method method do |path, **args|
           process method.to_sym, path, **args
         end