+* Alice starts creating a new page. In the meantime, Bob renames a
+ different page to that name. Alice should get an error message when
+ committing; and it should have conflict markers. Ie, this should work the
+ same as if Bob had edited the new page at the same time as Alice did.
+* Bob starts renaming a page. In the meantime, Alice creates a new page
+ with the name he's renaming it to. Here Bob should get a error message
+ that he can't rename the page to an existing name. (A conflict resolution
+ edit would also be ok.)