(null)
+- test:s:1
   |- test:x:1
   |- test:a:1
   |  \- test:b:1
   |     \- test:c:1
   |        \- test:x:2
   +- test:d:1
   |  \- test:e:2
   |     \- test:c:2
   |        \- test:x:3
