sdk: option to allow mint to specific address with mintFor

[andrevmatos]

Needed for _testing's mint functionality of #1692

Short description
Add an optional param to specificy the beneficiary of the mint transaction.

Definition of Done

• Steps to manually test the change have been documented
• Acceptance criteria are met
• Change has been manually tested by the reviewer (dApp)

Steps to manually test the change (dApp)

[codecov]

Codecov Report

Merging #1910 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1910   +/-   ##
=======================================
  Coverage   95.61%   95.61%           
=======================================
  Files         155      155           
  Lines        5793     5796    +3     
  Branches     1089     1089           
=======================================
+ Hits         5539     5542    +3     
  Misses        196      196           
  Partials       58       58           

Flag	Coverage Δ
#dapp	91.76% <ø> (ø)
#sdk	97.21% <100.00%> (+<0.01%)	⬆️
#sdk_e2e	65.49% <100.00%> (+0.04%)	⬆️
#sdk_unit	86.44% <0.00%> (-0.07%)	⬇️

Impacted Files	Coverage Δ
raiden-ts/src/raiden.ts	91.48% <100.00%> (+0.06%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 36efe62...0874921. Read the comment docs.

[weilbith]

Stone by stone. You did a lot of coding yesterday. Thanks for your hard work! 💪

[weilbith]

Hmm the docs say that the token contract can either define mint(address, uint256), mintFor(uint256, address) or increaseSupply(uint256, address). The last seem to be not relevant. But from the first two: what is the difference in behavior except the signature? Is there definition exclusive? Should we maybe check for both? Or is mintFor the only one that does what we want now?

[andrevmatos]

We don't support all these interfaces. If you look into the source of the CustomToken contract, you'll see it supports just 2 minting methods: mint(uint256), which mints for self, and mintFor(uint256, address), which allows minting for a 3rd party. This is a _testing function, used only on our testnets, and these are always deployed with this contract. It'd be hard for the SDK to support multiple contracts interfaces, so we went with what is actually used.