There is now a checkbox to prevent tests from copying twice. The checkbox is checked by default.
The "No Duplicates" checkbox will check #1 (Period), #3 (Test Type/Semester) and the test subject. If there is a test that already exists, it will not create a double.
If you need to create tests that can be multiple times in the same semester (weekly tests). Check the "Allow different dates" and the system will check #1, #2, #3 and the test subject.