For the benefit of our new folks and for posterity:

Many of our QA tests for CephFS are located in qa/tasks/cephfs/*.
These get run in teuthology with various cluster configurations. What
everyone will need to be able to do is develop these tests locally
without waiting for teuthology so you can rapidly find errors in your
test cases and development builds.

To do this, you need to use the qa/tasks/vstart_runner.py script. This
allows you to use a vstart cluster to execute your tests by providing
the necessary frameworks the tests expect.

On a development box*, build ceph. If you're just testing CephFS, you
can usually get away with a smaller build without rbd/rgw:

/do_cmake.sh -DWITH_PYTHON3:BOOL=ON -DWITH_BABELTRACE=OFF
-DWITH_MANPAGE=OFF -DWITH_RBD=OFF -DWITH_RADOSGW=OFF && time (cd build
&& make -j24 CMAKE_BUILD_TYPE=Debug -k)

Next, build teuthology:

git clone https://github.com/ceph/teuthology.git && cd teuthology &&
virtualenv ./venv && source venv/bin/activate && pip install --upgrade
pip && pip install -r requirements.txt && python setup.py develop

pip install -r requirements.txt fails on Fedora31, as it has python3 installed by default. https://pythonclock.org/

"""
ERROR: Command errored out with exit status 1:
command: /home/jcollin/workspace/teuthology/venv/bin/python3 -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-z2fktdug/functools32/setup.py'"'"'; __file__='"'"'/tmp/pip-install-z2fktdug/functools32/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' 
egg_info --egg-base /tmp/pip-install-z2fktdug/functools32/pip-egg-info
cwd: /tmp/pip-install-z2fktdug/functools32/
Complete output (1 lines):
This backport is for Python 2.7 only.
"""

I did the following on Fedora31 to successfully complete the setup:
$virtualenv -p /usr/bin/python2.7 myvenv
$source myvenv/bin/activate
$pip install -r requirements.txt


then mysqlclient fails with error:    
EnvironmentError: mysql_config not found

#dnf install community-mysql-devel-8.0.17-2.fc31.x86_64
$pip install -r requirements.txt

#dnf install libzstd-devel
$ pip install -r requirements.txt && python setup.py develop
Finished processing dependencies for teuthology==1.0.0

I need to run a test_ now. Hope this helps others.

Regards,
Jos Collin