System Under Test's, they can differ...

WHAT wil you Starting point

System to be tested

Web Interface
- With a third party
  - With (extra) hardware (f.e. handheld)
    - Test Option A
  - Without hardware
    - Test Option B
- Without a third party
  - With hardware
    - Test Option C
  - Without hardware
    - Test Option D (common)
Operating System Interface
- With a third party
  - With hardware
    - Test Option E
  - Without hardware
    - Test Option F
- Without a third party
  - With hardware
    - Test Option G
  - Without hardware
    - Test Option H (common)

So these are just EXAMPLES of different configurations of Systems Under Test. However, on a lower level, you probably test something like a module or a new functionality...

On an even lower level, you probably test something like a bug of that module or new little feature...

Once you have decided what is going to be tested, where the focus will be on, then you can determine what amount of attention it will get

And next how you are going to test it.

This whole System(s), big Module, average Functionality or small bug can be systematically checked in the Definition of Done.

Don't forget, these EXAMPLES of SUT configurations can life in different configurations of test LANDSCAPES.

System under test desert

For example: a web-interface that is going to be replaced by a Operating System Interface
or
a Operating System Interface that gets replaced by a new Web-Interface that also has to work on MOBILE.
or moving TO the cloud, moving FROM the cloud, a new server, test automation being introduced or...
... so 'test landscapes', the SUT is surrounded by it's test landscape context.

	2 SUT, 1 test landscape Two Systems Under Test evaluated within a single test environment, such as a desert, representing a (methaphoric) shared testing context.
	2 SUT, 1 test landscape Another depiction of two Systems Under Test in the same (methaphoric)desert environment, emphasizing consistent testing conditions for comparison.
	2 SUT, 2 test landscapes Two Systems Under Test evaluated in different environments (e.g., different companies or countries). Example: Country 1 excels in performance testing with cloud-based systems, while Country 2 specializes in security testing with local databases. They can still be part of only 1 test (to make this methaphore even funnier: communication from Mars to Earth f.e.) So now you have been shown some conceptual pictures about Systems Under Test and Test landscapes.... Let's talk about test processes, test planning, test strategy in the next chapters of Break software testing methodology. Note that! some Systems Under Test have a (sometimes thight) dependency with third party software! (like D&B, ICC, KVK) In the process of software testing (think of planning, strategy, testcase design, automation) you can't neglect this. Even more so: in some case you will have to work together, test together! sorry had to make this joke! (The cowboy (tester) is shooting on a moving target from a moving object, carrying a SUT)