output.txt

$ bash test.sh
Running virtualenv with interpreter /usr/local/bin/python3
Using base prefix '/usr/local/Cellar/python3/3.6.3/Frameworks/Python.framework/Versions/3.6'
New python executable in /Users/me/sotest/virtenv3/bin/python3.6
Also creating executable in /Users/me/sotest/virtenv3/bin/python
Installing setuptools, pip, wheel...done.
Running virtualenv with interpreter /usr/local/bin/python2
New python executable in /Users/me/sotest/virtenv2/bin/python2.7
Also creating executable in /Users/me/sotest/virtenv2/bin/python
Installing setuptools, pip, wheel...done.
Collecting toml
Installing collected packages: toml
Successfully installed toml-0.9.4
Collecting toml
Installing collected packages: toml
Successfully installed toml-0.9.4
Collecting toml
Installing collected packages: toml
Successfully installed toml-0.9.4
ok
ok
ok
ok
ok
ok

test.py

import toml

print("ok")

test.sh

rm -rf virtenv3 virtenv2 venv3

virtualenv -p python3 virtenv3
virtualenv -p python2 virtenv2
python3 -mvenv venv3

(
source virtenv3/bin/activate
pip install toml
)

(
source virtenv2/bin/activate
pip install toml
)

(
source venv3/bin/activate
pip install toml
)

(
source virtenv3/bin/activate
python test.py
)

(
source virtenv2/bin/activate
python test.py
)

(
source venv3/bin/activate
python test.py
)

virtenv3/bin/python test.py
virtenv2/bin/python test.py
venv3/bin/python test.py