ci: Fix CI by preventing running tests on venvs

Author: pawamoy

tests/test_project.sh

@@ -55,8 +55,10 @@ pycode="import sys; print(sys.version.split(' ', 1)[0].rsplit('.', 1)[0])"
 make run python -c "print('run: ', end=''); ${pycode}"
 make multirun python -c "print('multirun: ', end=''); ${pycode}"
 make allrun python -c "print('allrun: ', end=''); ${pycode}"
-version="$(python -c "${pycode}")"
-make "${version}" python -c "print('3.x: ', end=''); ${pycode}" | grep -F "${version}"
+if [ -n "${PYTHON_VERSIONS}" ]; then
+    version="$(python -c "${pycode}")"
+    make "${version}" python -c "print('3.x: ', end=''); ${pycode}" | grep -F "${version}"
+fi
 echo
 echo ">>> Formatting and asserting there are no changes"
 make format