"Couldn't find 'dub_test_root'. Make sure you are running tests with dub test"

Got the error with minimal dub application.

Steps to reproduce:

C:\test>dub init -n
Successfully created an empty project in 'C:\test'.
Package successfully created in .

C:\test>dub test
No source files found in configuration 'library'. Falling back to "dub -b unittest".
Performing "unittest" build using C:\D\dmd2\windows\bin\dmd.exe for x86_64.
test ~master: building configuration "application"...
Linking...
Running .\test.exe
Edit source/app.d to start your project.

C:\test>dub add silly
Adding dependency silly ~>1.0.2

C:\test>dub test
No source files found in configuration 'library'. Falling back to "dub -b unittest".
Performing "unittest" build using C:\D\dmd2\windows\bin\dmd.exe for x86_64.
test ~master: building configuration "application"...
C:\Users\andrey\AppData\Local\dub\packages\silly-1.0.2\silly\silly.d(15,2): Error: static assert:  "Couldn't find 'dub_test_root'. Make sure you are running tests with dub test"
C:\D\dmd2\windows\bin\dmd.exe failed with exit code 1.

D tools used:

C:\test>dub --version
DUB version 1.20.0, built on Mar  9 2020

C:\test>dmd --version
DMD32 D Compiler v2.091.0-dirty
Copyright (C) 1999-2020 by The D Language Foundation, All Rights Reserved written by Walter Bright