fuzz: add types.ParseCoin

[cuonglm]

Description

Add fuzzing for types.ParseCoin.

Updates #7921

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[cuonglm]

cc @odeke-em

[odeke-em]

LGTM, thank you @cuonglm. For an introduction, @cuonglm works with me at @orijtech and will also be sending changes.

[amaury1093]

I think a basic README would be useful.

I can see the corpus/*.seed files being used, but have no idea why the other files are committed. Also, would like to know who to run the fuzzer.

[alessio]

Great stuff. Can we move the fuzzy test data into testutil please?

I agree with @amaurymartiny too as I'd love to integrate the fuzzer in our buildsystem.

[cuonglm]

Go fuzz can be part of go1.17 https://go.googlesource.com/proposal/+/master/design/draft-fuzzing.md

In the meantime, I don't know what's the best way to do this, other than following go-fuzz readme. Any idea @odeke-em ?

[tac0turtle]

can you add a quick README file here. I realize we can go to go-fuzz to see how to run these but lets get some docs in here to avoid the extra step. It can also be a copy with minor adjustments of what is in the go-fuzz repo.

[tac0turtle]

@cuonglm could you please add a short readme on how to run these tests?

[cuonglm]

@cuonglm could you please add a short readme on how to run these tests?

Sure, to be clear, you mean add readme for how to run this with go-fuzz?

[tac0turtle]

Sure, to be clear, you mean add readme for how to run this with go-fuzz?

Yes, how to run them, what dependencies are required. This avoids the dev from going elsewhere to read docs.

[tac0turtle]

after linting is fixed we can merge this

[cuonglm]

after linting is fixed we can merge this

It seems weird, since when the golangci-lint error seems not related to this change. Maybe we can just merge this and fix in the fuzz-packages branch? cc @odeke-em