Add ERC20 and ERC777 fixed supply presets #2377

[ashwinYardi]

Open issue: #2377

Additions #

1. Added ERC20 preset contract with with fixed initial supply.
2. Added ERC777 preset contract with fixed initial supply.
3. Added tests for both the presets.

[frangio]

Thanks @ashwinYardi!

[stale]

Hi all!
This Pull Request has not had any recent activity, is it still relevant? If so, what is blocking it? Is there anything we can do to help move it forward?
Thanks!

[ashwinYardi]

@frangio @Skyge Some info about the testcases included:

Since the base contracts used in above presets, already have a full fledged test cases to cover the entire behavior, Only bare minimum test cases which help in establishing the high level behavior of preset contracts have been added. Again, I referred to test cases written for already added presets and it made sense to proceed this way.

Thanks and please let me know if there is anything missing or needs to be corrected, would be happy to do it immediately so that we can get this meged! ( PS. Sorry for not mentioning this info about testcases on PR's description ).

[frangio]

@ashwinYardi Sorry for taking so long to come back to this!

Thank you for explaining the rationale for what to test. I didn't remember the other presets followed the same approach to testing.

I'd like to see a few more changes in the tests before we merge this:

• Remove the context and describe "wrappers", since they don't serve any purpose here.
• Remove tests that we can assume correct from the base ERC777 contract:
  • returns a granularity of 1
  • returns 18 when decimals is called
• ERC20: add a test for the total supply

I also think the documentation needs a little bit of work. But this is something we can do if you prefer. If you'd like to take a stab at it you can take a look at the docs comments for the existing presets and follow a similar format. The docs for the constructor are missing too.

In order for the presets to show in the site, you need to add their names in contracts/presets/README.adoc.

[ashwinYardi]

Hi @frangio ! Thanks a lot for the feedback.

• Removed the unused context and describe "wrappers"
• Removed the suggested tests that can be assumed correct from base implementation
• Added a test for total supply in ERC20 preset
• Added a test for decrementing the total supply when tokens are burnt in ERC20 preset
• Gave a shot at improving documentation
• Added required entries in contracts/presets/README.adoc

[frangio]

Great work @ashwinYardi! I made a few small changes to the docs, added a changelog entry, and I realized I prefer to keep the defaultOperators argument in the same place as the ERC777 constructor so I changed that as well.