if...elif...else in Python

That’s the difference in Python between an if...elif...else and a series of ifs:

if a:
    do this
elif b:
    do that
elif c:
    do something else
else:
    print "none of the above"

is equivalent to (exactly the same as) this:

if a:
    do this
if (not a) and b:
    do that
if (not a) and (not b) and c:
    do something else
if (not a) and (not b) and (not c):
    print "none of the above"

As you can see, the elif...else notation allows you to write the same logic (the same control flow) without repeating the a condition over and over again.

Copied from here: https://www.codecademy.com/en/forum_questions/51684a3d4ce76309b4001b9c

How to create and manage python virtualenv?

Create, activate and deactivate virtualenv

cd my_project_folder

virtualenv .venv
. .venv/bin/activate

deactivate

Run a single python test with tox

This is the hint how to run a single or several specific functional and unit tests in python projects with tox.

Tox environment `functional`:

Run tests by the template of their name:
tox -e functional test_node_list

Run single test specifying full path:
tox -e ironicclient.tests.functional.osc.v1.test_baremetal_node_basic.BaremetalNodeTests.test_list

Run class of tests:
tox -e functional BaremetalNodeTests

Run specific test from class (including those under @ddt):
tox -e functional BaremetalNodeTests.test_delete

Unit tests (py27 for example):

Run several matching tests:
tox -e py27 do_port_show

Run single specific test from specified class:
tox -e py27 PortShellTest.test_do_port_show_invalid_fields