Add unittest

Add unittest

[   41s] + ./eval
[   41s]
[   41s] running 7 tests
[   41s] test features ... ok
[   41s] test complex ... ok
[   41s] test target_family ... ok
[   41s] test tiny ... ok
[   41s] test unstable_target_abi ... ok
[   41s] test wasm_family ... ok
[   41s] test very_specific ... ok
[   41s]
[   41s] test result: ok. 7 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.02s
[   41s]
[   41s] + for unit_test in '${unit_test_list}'
[   41s] + ./lexer
[   41s]
[   41s] running 6 tests
[   41s] test handle_cfg_keywords ... ok
[   41s] test handle_empty_value ... ok
[   41s] test handle_key_value ... ok
[   41s] test handle_short_key ... ok
[   41s] test handles_raw ... ok
[   41s] test strips_attribute ... ok
[   41s]
[   41s] test result: ok. 6 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.02s
[   41s]
[   41s] + for unit_test in '${unit_test_list}'
[   41s] + ./parser
[   41s]
[   41s] running 8 tests
[   41s] test fails_empty ... ok
[   41s] test ensures_not_has_one_predicate ... ok
[   41s] test fails_invalid_funcs ... ok
[   41s] test fails_malformed ... ok
[   41s] test fails_unbalanced_parens ... ok
[   41s] test fails_unbalanced_quotes ... ok
[   41s] test handles_simple_funcs ... ok
[   41s] test handles_single_predicate ... ok
[   41s]
[   41s] test result: ok. 8 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.02s