How to pass --DRT-covopt to dub test?

[Andre Pany]

Hi,

I have some issues to find out how I can pass --DRT-covopt to dub 
test.
I am pretty sure this should work, but dub doesn't like it:

dub test --coverage -- --DRT-covopt "dstpath:./cov"
...
Running .\cov-sample.exe dstpath:./cov
...

Is there s.th. I miss?

Kind regards
André