difference between functional testing and system testing?

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

Solution 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.

Solution 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".

Solution 3

System Testing includes both Function testing as well as non Function Testing Functional and non functional testing is done for a particular portion or is done step by step which becomes System testing.

Comments

[Harri]

Neither is part of the other. Functional tests should be done before system tests are done.

[SigmaX]

This contradicts Harri's answer, where non-functional testing would include unit testing, etc.

[SigmaX]

This answer contradicts psamagal's answer.

[Paulo Magalhães]

I don't see how this contradicts Harri's answer, but maybe it's my English that isn't good enough. Functional tests are created to validate requirements (the functionality of the product). And i don't refer in any part unit-testing for example as a functional testing.

[SigmaX]

Never mind. I think I misunderstood where Harri said "it tests a requirement (calculate tip), but not a specific function of the application." I thought he was implying that something that tests top-level requirements was not a functional test, and that only unit-level tests are. On second reading, I am mistaken.