$ tox -r  -e pypy37,pypy38 -- -n 0 --max-runs=1 -k venv_isnt_measured tests/test_process.py
with:

      with change_dir(venv_world):
          # Create a virtualenv.
 +        run_command("python -c 'import virtualenv; print(virtualenv)'")
          run_command("python -m virtualenv venv")
 -
 +        run_command("python -c 'import sys; print(sys.executable)'")
 +        1/0


pypy3.7:

    @command: "python -c 'import virtualenv; print(virtualenv)'"
    <module 'virtualenv' from '/Users/nedbatchelder/coverage/trunk/.tox/pypy37/site-packages/virtualenv/__init__.py'>

    --------------------------------------------------------------------------------
    @command: 'python -m virtualenv venv'
    created virtual environment PyPy3.7.10.final.0-64 in 529ms
      creator PyPy3Posix(dest=/private/var/folders/10/4sn2sk3j2mg5m116f08_367m0000gq/T/pytest-of-nedbatchelder/pytest-929/venv_world0/venv, clear=False, no_vcs_ignore=False, global=False)
      seeder FromAppData(download=False, pip=bundle, setuptools=bundle, wheel=bundle, via=copy, app_data_dir=/Users/nedbatchelder/Library/Application Support/virtualenv)
        added seed packages: pip==21.2.4, setuptools==58.1.0, wheel==0.37.0
      activators BashActivator,CShellActivator,FishActivator,NushellActivator,PowerShellActivator,PythonActivator

    --------------------------------------------------------------------------------
    @command: "python -c 'import sys; print(sys.executable)'"
    /Users/nedbatchelder/coverage/trunk/.tox/pypy37/bin/python

pypy3.8:

    @command: "python -c 'import virtualenv; print(virtualenv)'"
    <module 'virtualenv' from '/Users/nedbatchelder/coverage/trunk/.tox/pypy38/lib/pypy3.8/site-packages/virtualenv/__init__.py'>

    --------------------------------------------------------------------------------
    @command: 'python -m virtualenv venv'
    created virtual environment PyPy3.8.12.final.0-64 in 1306ms
      creator PyPy3Posix(dest=/private/var/folders/10/4sn2sk3j2mg5m116f08_367m0000gq/T/pytest-of-nedbatchelder/pytest-930/venv_world0/venv, clear=False, no_vcs_ignore=False, global=False)
      seeder FromAppData(download=False, pip=bundle, setuptools=bundle, wheel=bundle, via=copy, app_data_dir=/Users/nedbatchelder/Library/Application Support/virtualenv)
        added seed packages: PyContracts==2.0.1, attrs==21.2.0, backports.entry_points_selectable==1.1.0, backports.functools_lru_cache==1.6.4, decorator==5.1.0, distlib==0.3.3, execnet==1.9.0, filelock==3.3.1, flaky==3.7.0, future==0.18.2, hypothesis==6.23.1, iniconfig==1.1.1, packaging==21.0, pip==21.2.4, platformdirs==2.4.0, pluggy==1.0.0, py==1.10.0, pyparsing==2.4.7, pytest==6.2.5, pytest_forked==1.3.0, pytest_xdist==2.4.0, qualname==0.1.0, setuptools==58.1.0, six==1.16.0, sortedcontainers==2.4.0, toml==0.10.2, tomli==1.2.1, virtualenv==20.8.1, wheel==0.37.0
      activators BashActivator,CShellActivator,FishActivator,NushellActivator,PowerShellActivator,PythonActivator

    --------------------------------------------------------------------------------
    @command: "python -c 'import sys; print(sys.executable)'"
    /Users/nedbatchelder/coverage/trunk/.tox/pypy38/bin/python


Why:
- is the virtualenv at a different place?
- are the seed packages installing everything for 3.8?

virtualenv has a bug about it: https://github.com/pypa/virtualenv/issues/2182