In Travis with Python 3.4, virtualenv 20.0.19 does not seem to install a pip into a newly created virtualenv when creating it while a virtualenv is already acrive. "which pip" returns the pip from the first virtualenv after the new one is created and active. It fails only on Python 3.4 (the errors with pypy in the Travis logs below have a different cause). virtualenv before 20.0.19 does not have that behavior and succeeds on Python 3.4.
Version and location of Python and Pip after having activated the second virtualenv: Note that Python is shown to come from the correct second virtualenv while Pip is shown to come from the incorrect first virtualenv that Travis had set up:
Python version: Python 3.4.8 from /home/travis/build/pywbem/pywbem/tmp_installtest/virtualenvs/pywbem_test_test1/bin/python
Pip version: pip 19.1.1 from /home/travis/virtualenv/python3.4.8/lib/python3.4/site-packages/pip (python 3.4)
To see this in the Travis logs, search for "Creating virtualenv:" case sensitively (around line 2500):