Can you give an example of using these terms, "network access, database, file system, ...", to test an application? Can you give such example with a procedure with step by step?

In my mind, there is a procedure. For example, you may setup an entry main method, and then in the main method you call method A, B, C, and finally you trigger the network access function, D. After you have such path to trigger D, and then you begin to feed small, medium and large dataset to the main function.

If this is the case, then I think you are talking about an input data generation step during an concrete integration testing over a group of components.

Look forward to hear you back, and best wishes.