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.