Generally, the test the system will divide the test into sections first. Each subsection when tested and then bring together, and then test the whole system. Those acts, which we call that system tester test.
In general, the test will be divided into sub-sections before testing. When each part of the test is completed. Bring together and test the system. We call those who serve the system tester.
In general, the test system is divided into a test subset. When each of the subsets tested. The combined test system. Which we call those who act test system that tester.