dlang comes with dub a package manager and buildsystem at the same time. This is now part of the reference compiler so you can start your project simply with dub init. I suggest to add unit-threaded as dependency to get a nice testing framework in place. The details can get tricky so I suggest to come up with several dub configurations:

• application: if your module is an application this uses source/app.d to start your program
• library: if you want to reuse your module, make it a proper library.
• unittest: for me the following block works best:

  configuration "unittest" {
    targetType "executable"
    targetName "unittest"
    buildOptions "coverage"
  
    dependency "unit-threaded" version="==0.7.22"
    preBuildCommands "dub run unit-threaded -c gen_ut_main -- -f gen/testsuite.d"
    mainSourceFile "gen/testsuite.d"
    excludedSourceFiles "source/app.d"
  }

• ut: for running quick unittests with unit-threaded:

  configuration "ut" {
    targetType "executable"
    targetName "ut"
    buildOptions "coverage"
  
    versions "unitThreadedLight"
    dependency "unit-threaded" version="==0.7.22"
    mainSourceFile "gen/testsuite.d"
    excludedSourceFiles "source/app.d"
  }

With this enabled you can run dub test -c ut || dub test to get a quick feedback if all tests are green, and a detailed feedback if tests are red. By specifying coverage as build options you also get the dlang builtin coverage when running your tests (watch out for lst files).