Regression Testing, Smoke Testing and Sanity Testing? - Interview question asked in Naggaro

Which come first to next place in testing Regression Testing, Smoke Testing and Sanity Testing?

Smoke Testing - 

1) A Smoke test is designed to touch every part of the application in a cursory way. 
2) Smoke testing is conducted to ensure whether the most crucial functions of a program are working 
3) Smoke testing is normal health check up to a build of an application before taking it to testing in depth. 

Sanity Testing - 
1) A sanity test is a narrow regression test that focuses on one or a few areas of functionality. Sanity testing is usually narrow and deep. 
2) Sanity testing is a cursory testing, it is performed whenever a cursory testing is sufficient to prove the application is functioning according to specifications. 

Regression Test - 
1) The intent of regression testing is to provide a general assurance that no additional errors were introduced in the process of fixing other issues.

 System Testing:- It is end to end testing.Where testing environment is just similar to production environment.here we check 1.Region Specific 2.Page Specific 3.Text Specific 4.Time duration specific 5.Cost specific. 

We start system testing when- minimum number of features are ready. 
basic functionality of all the module must be working.

a. Smoke Testing : To make sure the build is not breaking and can be testable. 
b. Sanity Testing : To check the basic functionality without going into detail. 
c. Regression: To make sure the existing functionality is not been impacted because of new changes.

 First smoke test checking basic availibility 
Then sanity check: basic functionalities work as required 
then regression test : control all desired functionalities