See https://www.martinfowler.com/bliki/StranglerApplication.html for more info on the used pattern for refactoring legacy applications.
Introduced class `BenchmarkDriver` as a beginning of strangler application that will gradually replace old functions. Used it instead of `get_tests()` function in Benchmark_Driver.
The interaction with Benchmark_O is simulated through mocking. `SubprocessMock` class records the invocations of command line processes and responds with canned replies in the format of Benchmark_O output.
Removed 3 redundant lit tests that are now covered by the unit test `test_gets_list_of_all_benchmarks_when_benchmarks_args_exist`. This saves 3 seconds from test execution. Keeping only single integration test that verifies that the plumbing is connected correstly.
The imports are a bit sketchy because it doesn’t have `.py` extension and they had to be hacked manually. :-/
Extracted `parse_args` from `main` and added test coverage for argument parsing.
