Add unittest

Add unittest
[   26s] + for unit_test in '${unit_test_list}'
[   26s] + ./test_autotrait
[   26s]
[   26s] running 1 test
[   26s] test test ... ok
[   26s]
[   26s] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.01s
[   26s]
[   26s] + for unit_test in '${unit_test_list}'
[   26s] + ./test_identifier
[   26s]
[   26s] running 2 tests
[   26s] test test_eq ... ok
[   26s] test test_new ... ok
[   26s]
[   26s] test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.07s
[   26s]
[   26s] + for unit_test in '${unit_test_list}'
[   26s] + ./test_version
[   26s]
[   26s] running 10 tests
[   26s] test test_align ... ok
[   26s] test test_display ... ok
[   26s] test test_eq ... ok
[   26s] test test_ge ... ok
[   26s] test test_gt ... ok
[   26s] test test_le ... ok
[   26s] test test_lt ... ok
[   26s] test test_ne ... ok
[   26s] test test_parse ... ok
[   26s] test test_spec_order ... ok
[   26s]
[   26s] test result: ok. 10 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.02s
[   26s]
[   26s] + for unit_test in '${unit_test_list}'
[   26s] + ./test_version_req
[   26s]
[   26s] running 19 tests
[   26s] test test_any ... ok
[   26s] test test_basic ... ok
[   26s] test test_caret ... ok
[   26s] test test_cargo3202 ... ok
[   26s] test test_default ... ok
[   26s] test test_digit_after_wildcard ... ok
[   26s] test test_eq_hash ... ok
[   26s] test test_greater_than ... ok
[   26s] test test_exact ... ok
[   26s] test test_leading_digit_in_pre_and_build ... ok
[   26s] test test_less_than ... ok
[   26s] test test_logical_or ... ok
[   26s] test test_multiple ... ok
[   26s] test test_parse_errors ... ok
[   26s] test test_pre ... ok
[   26s] test test_tilde ... ok
[   26s] test test_whitespace_delimited_comparator_sets ... ok
[   26s] test test_wildcard ... ok
[   26s] test test_wildcard_and_another ... ok
[   26s]
[   26s] test result: ok. 19 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.03s