message: cherry-pick rdflib mock changes from Sharon's branch
diff: @@ -84,8 +84,10 @@ export class Fetcher {
  load () {
  }
  }
  -export function namedNode() {
  - return {}
  +export function namedNode(str: string) {
  + return {
  + uri: str
  + }
  }
  export function NamedNode() {
  }
  @@ -94,4 +96,5 @@ export function Namespace() {
  }
  export class UpdateManager {
  editable() {}
  + update() {}
  }
  