Whenever I save the app.d file in DDT, the file gets compiled using dub build. What to do, when I want to customize the options, for instance to get unittests (i.e. run dub build -b unittest)?
Editing run/debug configurations doesn't help.
A D project already has different build targets, including one for building (and running) the tests. You can also configure each target with additional DUB options. See more info here: https://github.com/DDT-IDE/DDT/blob/latest/documentation/UserGuide.md#project-building