Disable when inside tests

[ehmicky]

When a binary is being tested, update-notifier should probably not be called since:

• this would not work with snapshot testing, where the binary output is expected to match a specific string
• this might make tests fail if update-notifier throws an error (e.g. if there is no network connection)
• this makes tests slower
• this adds no value (since only package maintainers run tests and do not need to be notified about new versions)

Now, knowing whether update-notifier is currently run inside a test might be tricky.

I think one naive approach which might cover some test runners would be to check for NODE_ENV. I.e. if process.env.NODE_ENV === 'test', disable update-notifier (like this is currently done with is-ci).

Note: I can provide with a PR.

What do you think?

[sindresorhus]

I think one naive approach which might cover some test runners would be to check for NODE_ENV. I.e. if process.env.NODE_ENV === 'test', disable update-notifier (like this is currently done with is-ci).

👍 The behavior should be clearly documented though.

[ehmicky]

PR at #173.