Fix failed tests that are relying on the method_missing method.

lib/wings/hydra/pcdm/models/concerns/pcdm_valkyrie_behavior.rb

@@ -137,6 +137,24 @@ def original_file
         af_object.original_file
       end
 
+      ##
+      # @return [Boolean] whether this instance is an audio.
+      def audio?
+        af_object = Wings::ActiveFedoraConverter.new(resource: self).convert
+        af_object.audio?
+      end
+
+      # TODO: This can be removed when we upgrade to ActiveFedora 12.0
+      # @return [String] the etag from the response headers
+      #
+      # @raise [RuntimeError] when the resource is new and has no etag
+      # @raise [Ldp::Gone]    when the resource is deleted
+      def etag
+        raise "Unable to produce an etag for a unsaved object" unless persisted?
+        af_object = Wings::ActiveFedoraConverter.new(resource: self).convert
+        af_object.ldp_source.head.etag
+      end
+
       # @param valkyrie [Boolean] Should the returned ids be for Valkyrie or AF objects?
       # @return [Enumerable<Hydra::Works::Work>] The works this work is contained in
       # @note This method avoids using the Hydra::Works version of parent_works because of Issue #361