What version are you running?
4.0
What steps will reproduce the problem?

download the sdist from PyPI (https://pypi.org/project/RBTools/#files)
unpack it
look into rbtools/rbtools/clients/tests


What is the expected output? What do you see instead?
There should be testdata directory, but it is missing.

Without this directory (and its content) some tests fails.
What operating system are you using?
NA
Attach the debug out from the command.
NA
Please provide any additional information below.
NA