ISTQB definition:
According to the ISTQB foundation, we have the following types of testing:
Functional testing;
Non-functional testing;
White-box testing;
Change-related testing. Non-functional testing, as functional testing, is performed at all test levels (To get familiar with test levels, follow the video: What levels of testing do you know)
Non-functional testing includes, but is not limited to:
Performance testing;
Load testing;
Stress testing;
Volume testing
Usability testing; Maintainability testing; Reliability testing; Portability testing; Security testing;
Change-related testing includes:
Confirmation testing (re-testing); Regression testing.
Human language:
As you noticed from the ISTQB foundation, there are 4 types of testing:
Functional testing;
Non-functional testing;
White-box testing;
Change-related testing. Of course, there are a lot of subtypes of testing. You can see them in the picture below:
Besides types, that are mentioned in the scheme, there is one additional category: Uncategorized, Which includes:
Manual testing and Automation testing;
Positive testing and Negative testing.
Functional testing - tests pertaining to what the system should do, i.e. what the user or customers want from the system, as documented in the Requirements and Functional specifications;
Non-functional testing - tests pertaining to how the system should behave e.g. reliability, response times, throughput, data storage, security, and compliance to legal, safety, or industry-specific standards. These should be specified as part of the Requirements Specs and should be testable. Some examples of non-functional testing are Usability, Install abilities, Portability, Inter-operability, Maintainability, Security, Performance, Load, Stress, etc.;
White-box testing - In this type of testing, the focus is on assessing the thoroughness of testing. For Functional testing, this could be how many features or functions of the total have been tested so far. We could also look at the code to see how many lines of code have been exercised by tests, how many decisions have been exercised etc, these are part of the statement, decision coverage. And fall under White box testing techniques.
Change-related testing - when the system undergoes changes due to defect fixes, two types of tests are needed; one to verify the change has not broken the existing, working code and the second to ensure the defect has been fixed. These tests are called Regression and Confirmation testing.
Conclusion:
So, if you are asked at an interview: What Types of testing do you know? The best way to answer is:
There are 4 types of testing:
Functional testing;
Non-functional testing;
White-box testing;
Change-related testing.