Refactored to use the 'unittest' module (test conditions in code, rather
than verifying text output), use pre-generated repository files, and
discontinue use of the old repository tools. Expanded comments and modified
previous setup.
Minor edits to slow_retrieval_server.py.
Add missing else clauses (to detect when TUF fails to prevent an attack) for a couple of the integrations tests.
Refactored 'test_endless_data_attack.py' to use the 'unittest' module (test
conditions in code, rather than verifying text output), use pre-generated
repository files, and discontinue use of the old repository tools. Minor
edits to the test cases.