Add tests for coercing bad values to a boolean

[DanielHeath]

I was going to open an issue, but thought that including code would help illustrate, so it's a PR instead.

Currently, if you supply "" for a boolean parameter, it does not get coerced at all - instead, it gets passed through.

I think that's confusing and inconsistent; it would be better to return Nil. Is that a sensible change?

[grape-bot]

	1 Warning
⚠️	Unless you’re refactoring existing code, please update CHANGELOG.md.

	1 Message
📖	We really appreciate pull requests that demonstrate issues, even without a fix. That said, the next step is to try and fix the failing tests!

Here's an example of a CHANGELOG.md entry:

* [#2045](https://github.com/ruby-grape/grape/pull/2045): Add tests for coercing bad values to a boolean - [@DanielHeath](https://github.com/DanielHeath).

Generated by 🚫 danger

[dnesteryuk]

It would be better to move tests to that place.

[dnesteryuk]

I would prefer to coerce an empty string to false in this case 🤔 The reason of the current behavior is there.

[DanielHeath]

IMO an empty string is an invalid value to assign a boolean and should be treated the same as (eg) passing a string to a numeric value.

[myxoh]

I tend to agree I would expect nil here as well. Thanks for adding the test!

[dblock]

I think I agree, I'd want this to be nil. Would take a PR. What else breaks?

[dnesteryuk]

Dry-types treats an empty string as invalid for the boolean type 🤔

Dry::Types::CoercionError ( cannot be coerced to false)

[dblock]

Dry-types treats an empty string as invalid for the boolean type 🤔

Dry::Types::CoercionError ( cannot be coerced to false)

Interesting. I don't know ;)

[dnesteryuk]

@DanielHeath thanks for the test, the request was implemented 😉