How to test if composer.lock is up to date?

Question

During development (multiple people in the team) sometimes composer install returns:

Warning: The lock file is not up to date with the latest change

Answer 1

on newer versions (I suppose 1.3+) you can run the following:

$ composer validate --no-check-all --no-check-publish

Which might output something like this (with a catchable error exit code):

./composer.json is valid for simple usage with composer but has
strict errors that make it unable to be published as a package:
See https://getcomposer.org/doc/04-schema.md for details on the 
schema
The lock file is not up to date with the latest changes in composer.json, it is recommended that you run `composer update`.