difference between functional testing and system testing? [closed]

Question

I heard that system testing has two types

1)functional Testing 2)Non functional testing

But later in another website i have seen below statements

In the types of functional testing following testing types should be cover:

Unit Testing
Smoke testing
Sanity testing
Integration Testing
Interface Testing
System Testing
Regression Testing
UAT

I am confused, Please clarify me that whether the system testing includes functional or functional testing includes system testing and the sequence of these testings(functional is performed first or system)

Thanks

Answer 1

Functional testing aims to figure out whether given functionality works as specified. System testing aims to figure out whether the whole system fulfills the requirements given to it.

So in functional testing you test that given part of the whole system functions in a specified way. And in system testing you test the system as a whole fulfills the requirements given to it.

For example testing that 1+1=2 tests the plus function and sum function. And thus is a functional test. Testing whether user can calculate correct amount of tip using the calculator or not, is a system test, since it tests a requirement (calculate tip), but not a specific function of the application.

And non-functional testing includes stuff like usability and performance.

Answer 2

Functional testing are based on an analysis of requirements specification of a component or system.

Non-functional testing includes, but is not limited to, performance testing, load testing, stress testing, usability testing, maintainability,reliability, portability. It is the testing o how the system works.

You can call System Testing as a level of Test, instead Functional Testing is a Test Type. And System testing should investigate functional a non-functional areas of the system.

You could find more information on this subject if you read for example "ISQTB - Foundation Level Syllabus".