Definition:
A Sanity Test or Sanity Check is not just confined or limited to the context of programming or software engineering. A Sanity Test is just a casual term that means you’re testing/validating some information to make sure that it conveys the clear information and follows the simple logic. It’s a simplest way of ensuring and confirming that afore mentioned details makes sense to them from everyone’s perspective.
In the software context, a sanity test is the subset of regression testing, performed when there is no enough time left for testing. This is a surface level testing performed by QA Engineer to ensure that the menus, functions, and commands available in the product are working fine.
A Sanity Check can also be performed in Iteration planning to check if the work is achievable in the present iteration, according to the team’s plan.
Further Reading:
Disciplined Agile Delivery: A Practitioner’s Guide to Agile Software Delivery in the Enterprise by Scott W.Ambler & Mark Lines