Add session.interactive to easily determine if Nox is being run by a human.

[theacodes]

How would this feature be useful?
In many cases its useful to know if nox is being run in an actual terminal or via CI or some other "headless" means.

Describe the solution you'd like
A new property on Session called interactive. It would look like this:

@nox.session
def docs(session):
    if session.interactive:
        session.run("sphinx-autobuild", ...)
    else:
        session.run("sphinx")

[dhermes]

Why can't nox users just call sys.stdout.isatty()?

[theacodes]

They can. But why make it harder than it needs to be?

[theacodes]

Also, we could add flags such as --non-interactive to force session.interactive to be false.

[dhermes]

But why make it harder than it needs to be?

Well session.interactive and sys.stdout.isatty() are about the same number of characters.

The --non-interactive flag is another story though.

[theacodes]

True, but one requires (a) an import and (b) remembering what it is. I actually filed this issue after forgetting what it was and having to look it up for the 20th time.

…

On Thu, May 16, 2019 at 8:58 PM Danny Hermes ***@***.***> wrote: But why make it harder than it needs to be? Well session.interactive and sys.stdout.isatty() are about the same number of characters. The --non-interactive flag is another story though. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#189>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAB5I47NVIPZ24WEMNJBSY3PVYUOHANCNFSM4HNIVRUA> .

[AGeekInside]

I took a stab at adding the interactive attribute. There is a pull request with the initial changes to add the interactive attribute. I have not added the --non-interactive flag yet.

[theacodes]

This was implemented in #196