Improve test suite for a broader range of cases more efficiently

[fennecJ]

As noted in #151 , the current test suite only accepts tests where the final result is between 0 and 255 (a byte). This restriction makes it difficult to perform certain tests.

For example, when testing multi-digit hexadecimal values with the Fibonacci function, such as fib(0x10) = 987, the test must be written as:

(fib(0x10) - 987) == 0

Because final result exceed 255. This approach is somewhat awkward and unintuitive. Ideally, we should be able to test the result directly without needing to fit everything within the byte range. Expanding the range of accepted results or modifying the mechanism for capturing return values could make the test suite more flexible and easier to use for larger values.