Check for negative amounts in the token methods

[mosmartin]

What was the problem?

This PR resolves #8470

How was it solved?

Added -ve amount checks

How was it tested?

Added unit tests. npm t token/method

[codecov]

Codecov Report

Merging #8559 (2a010c6) into release/6.0.0 (ba05905) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 2a010c6 differs from pull request most recent head e7e6724. Consider uploading reports for the commit e7e6724 to get more accurate results

Additional details and impacted files

@@              Coverage Diff               @@
##           release/6.0.0    #8559   +/-   ##
==============================================
  Coverage          83.31%   83.31%           
==============================================
  Files                593      593           
  Lines              22296    22300    +4     
  Branches            3277     3279    +2     
==============================================
+ Hits               18575    18579    +4     
  Misses              3721     3721           

Impacted Files	Coverage Δ
framework/src/modules/token/method.ts	96.79% <100.00%> (+0.04%)	⬆️

[bobanm]

Looks good. Just one comment. Some test cases check only for negative amounts, while some others test both for negative and zero. That is not consistent, but also might be redundant.

I think it is enough to test that the amount is negative, as it is handled in the tested methods by the same conditional:

if (amount <= BigInt(0))