Dub and unit-threaded import problem

[Casey via Digitalmars-d-learn]

Hello,

I'm just starting a small project with dub and unit-threaded, but 
I'm getting an issue where the file "unit_threaded.d" cannot be 
found.

Details:

DMD version: DMD64 2.070.0

Dub version: 0.9.24

Dub Config:

{
     "name": "pst",
     "targetType": "executable",
     "targetPath": "bin",
     "configurations": [
         {
             "name": "unittest",
             "preBuildCommands": [
                 "dub run unit-threaded -c gen_ut_main -- -f 
bin/ut.d"
             ],
             "mainSourceFile": "bin/ut.d",
             "excludedSourceFiles": ["source/app.d"],
             "dependences": {
                 "unit-threaded": "~>0.6.3"
             }
         }
     ]
}

I haven't created any tests at this time.  It's a bare project.  
I just wanted to make sure the dub config worked before I started 
coding.  I feel I'm missing something very simple.  I just don't 
see it.