What is Sanity Testing?

Sanity Testing is subset of Regression Testing.Sanity Testing is verifying the "Rationality" of the system.

After receiving a software build with minor changes in functionality or code sanity testing is performed to ensure that the bugs have been fixed and no further issues are introduced due to these changes.The goal is to determine that the proposed functionality is working roughly as expected.If sanity test fails build is rejected to save the time.

Sanity testing is usually not documented.

Example: 

 Suppose if a project consists of different modules like Login,User Detail,Task Creation.Now in the login page if the username field accepts less than 8 alpha numeric in username text box which is against the requirement thus leading it to a bug.So the bug is raised by testing team to the development team.After the bug is fixed by development team the testing team checks the other modules to ensure that there are no changes in another modules.We ensure that we as a testing team do not perform in depth testing of other modules because of short time.

Sanity Testing is usually performed by Software Testers.