+ At least CMake 3.4.0 refuses to build SessionTest using the
  old `add_test` syntax without the `NAME` and `COMMAND` arguments.
+ The CreateAndSaveEdges python test failed because the
  operator definition changed (to use associations instead of a
  ModelEntityItem) but the test did not.
+ At least one discrete model was living past the end of the
  session, causing a crash at the exit of the CreateAndSaveEdges
  python test. This may be a bug, but at least the tests pass
  with the safety check in the `ItemWatcher` callback.