Hi @llenodo thanks for the PR, can you get CI passing and I'll be happy to merge these in. Looks like it just needs the specs to have the updated names.

Do you know if this is a change with a later activesupport? Trying to decide if we should restrict on anything with this change since older versions of something will still try the lowercase version.

Tests are passing now, ran into some issues with JsonIodocsWriter so changed the name back. Could be due to different version of activesupport in the code here vs my project (rails 5.1)

Thanks!

For me json_writer.classify returns JsonWriter - tested both on Rails 5.1 and 5.2. When tried to use rspec_api_documentation from master now I have an error uninitialized constant RspecApiDocumentation::Writers::JsonWriter.

I think this PR should be reverted and problem investigated with more details.

I wonder if there was an active support inflection set up in OP's setup. In any case, rather than classifying, you probably want to register the formatter names like I did in AMS https://github.com/rails-api/active_model_serializers/blob/f3a19bd515330751083c0a70b8f57d792de0d788/lib/active_model_serializers/adapter.rb

The examples in the readme are broken now.
You have to use all caps for json config.format = :JSON
as @bf4 mentions here #382 (comment).

I'd prefer if all the formats were the same case, or case insensitive.
Is that coming in the next release?