To deal with variety in target attributes and their expected outputs,
the test parameters are categorized into traits, thus the test program
could define test parameters in a more structured way, without having
to pass multiple tightly-coupled parameters to test functions.
- Make the naming of test cases less ambiguous, e.g., rename
"missing_input_file" to "missing_input_arg" or "input_file_not_found"
- Unify the error messages on input/output options
