928 bug parseunits throws on numbers below 01

[lucanicoladebiasi]

Description

The code fixes a bug in the function unitsUtils.parseUnits in the file packages/core/src/utils/units/units.ts leading to include non meaningful digits in BigNumber conversion to string to be parsed as bigint.

New tests are introduced to compare ethers behaviour with the drop-in functions provided by unitUtils, the latter are based on bignumber.js library.

The bignumberjs library configures its setting - specifically about the fixed digits precision and rounding methods - globally: this means if some code using this SDK needs to change BigNumber settings, the behaviour of unitUtils functions is altered in a potentially incorrect way.

This code stores the configuration of BigNumber, at the beginning of the execution of the format/parse functions, set it as needed to assure 80 meaningful digits and BigNumber.ROUND_HALF_UP rounding methods prescribed by Ethereum specifications, restoring the configuration when the functions return. This enhancement prevent BigNumber global settings collides with unitUtils needed setting.

Fixes # 928.

Type of change

Please delete options that are not relevant.

• [x] Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• [x] yarn:unit
• [x] yarn:solo

Test Configuration:

• Node.js Version: v20.14.0
• Yarn Version: 1.22.22

Checklist:

• [x] My code follows the coding standards of this project
• [x] I have performed a self-review of my code
• [x] I have commented on my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] New and existing integration tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules
• [x] I have not added any vulnerable dependencies to my code

[github-actions[bot]]

Test Coverage

Summary

Lines	Statements	Branches	Functions
	100% (3390/3390)	100% (783/783)	100% (701/701)

Title	Tests	Skipped	Failures	Errors	Time
core	485	0 :zzz:	0 :x:	0 :fire:	1m 4s :stopwatch:
network	660	0 :zzz:	0 :x:	0 :fire:	3m 43s :stopwatch:
errors	48	0 :zzz:	0 :x:	0 :fire:	11.237s :stopwatch: