Run the unit test suite.

def unit(session):
    """Run the unit test suite."""

    # Testing multiple version of django
    # See https://www.djangoproject.com/download/ for supported version
    django_deps_27 = [
        ('django==1.8.19',),
        ('django >= 1.11.0, < 2.0.0dev',),
    ]

    if session.virtualenv.interpreter == '2.7':
        [default(session, django_dep=django) for django in django_deps_27]
    else:
        default(session)