What is difference between Priority and Severity?

ISTQB Definition(priority: The level of (business) importance assigned to an item.)

Priority of a bug  is impact on application business. majorly bugs are having impact on business always . Impact can be differ of a bug at application. Hence priority  can be define in many types as per industry aspects. 
Mostly priority is categorized as High, medium and Low.
For example :  Material calculator is not function in inventory system. This issue is of High priority.



ISTQB Definition(severity: The degree of impact that a defect has on the development or operation of a component or system.)


Severity is measured by the impact of bug at application functions.  it normally indicates, how functioning is impacting application working. Severity is also organization specific. but as standards.
Five types are define.


Blocker: This leads to state when no further testing is possible.
Critical:  User is having data lose, crashes,exception in execution but application can tested.
Major: A function is not working.
Minor: A function is not working in few aspects.
Trivial: Insignificant  impact of issue at application.

What is difference between Smoke testing and Sanity Testing?

Smoke testing and Sanity testing is same as per all standards.
 But in industry specific term, it is is quite different. testing takes place in both manner first basic functional testing, basic functional testing with all positive aspects. smoke is execute all functional test scenario required priority base positive test cases. but in sanity tester put all positive test case with basic testing as well as few negative test cases if required. hence we just put little more efforts in sanity testing according industry aspects.

How ever Sanity is like regression testing but it does not cover all parts of application which may leads to existence of few defects. On the other hand Sanity is quickest way to find all critical bugs which can be cause of failure of any application.

Back Ground:

Smoke testing has been introduce in pipe industries for testing pipe leakage, Sanity is used in weather calculation. both are actually used to produce quick result.