What is the difference between smoke testing and sanity testing?

Sanity testing

Sanity testing is the subset of regression testing and it is performed when we do not have enough time for doing testing.

Sanity testing is the surface level testing where QA engineer verifies that all the menus, functions, commands available in the product and project are working fine.

Example

For example, in a project there are 5 modules: Login Page, Home Page, User's Details Page, New User Creation and Task Creation.

Suppose we have a bug in the login page: the login page's username field accepts usernames which are shorter than 6 alphanumeric characters, and this is against the requirements, as in the requirements it is specified that the username should be at least 6 alphanumeric characters.

Now the bug is reported by the testing team to the developer team to fix it. After the developing team fixes the bug and passes the app to the testing team, the testing team also checks the other modules of the application in order to verify that the bug fix does not affect the functionality of the other modules. But keep one point always in mind: the testing team only checks the extreme functionality of the modules, it does not go deep to test the details because of the short time.

Sanity testing is performed after the build has cleared the smoke tests and has been accepted by QA team for further testing. Sanity testing checks the major functionality with finer details.

Sanity testing is performed when the development team needs to know quickly the state of the product after they have done changes in the code, or there is some controlled code changed in a feature to fix any critical issue, and stringent release time-frame does not allow complete regression testing.

Smoke testing

Smoke Testing is performed after a software build to ascertain that the critical functionalities of the program are working fine. It is executed "before" any detailed functional or regression tests are executed on the software build.

The purpose is to reject a badly broken application, so that the QA team does not waste time installing and testing the software application.

In smoke testing, the test cases chosen cover the most important functionalities or components of the system. The objective is not to perform exhaustive testing, but to verify that the critical functionalities of the system are working fine. For example, typical smoke tests would be:

• verify that the application launches successfully,
• Check that the GUI is responsive