* Set up GitHub actions CI
* Remove simplecov entirely for now
* Fix deprecations
* Relax dev deps
* Address Rails 6.0 blocking hosts
* Rails 6.1 content type changed to application/json; charset=utf-8
* Test a few more rubies and rails
* Stop testing grape. We should drop grape support
```
/home/runner/work/active_model_serializers/active_model_serializers/vendor/bundle/ruby/2.6.0/gems/grape-0.19.0/lib/grape/error_formatter.rb:16: warning: in `formatters': the last argument was passed as a single Hash
/home/runner/work/active_model_serializers/active_model_serializers/vendor/bundle/ruby/2.6.0/gems/grape-0.19.0/lib/grape/error_formatter.rb:21: warning: although a splat keyword arguments here
Run options: --seed 23470
..........................................................................................................................................................................................................................................................................................................................................................................................................................................E
ActiveModelSerializers::GrapeTest#test_render_helper_passes_through_options_correctly:
NoMethodError: undefined method `[]' for nil:NilClass
bin/rails test /home/runner/work/active_model_serializers/active_model_serializers/test/grape_test.rb:126
W, [2020-12-29T02:27:48.991413 #2790] WARN -- : You are setting a key that conflicts with a built-in method Hashie::Mash#size defined in Hash. This can cause unexpected behavior when accessing the key as a property. You can still access the key via the #[] method.
W, [2020-12-29T02:27:48.991505 #2790] WARN -- : You are setting a key that conflicts with a built-in method Hashie::Mash#size defined in Hash. This can cause unexpected behavior when accessing the key as a property. You can still access the key via the #[] method.
W, [2020-12-29T02:27:48.991581 #2790] WARN -- : You are setting a key that conflicts with a built-in method Hashie::Mash#size defined in Hash. This can cause unexpected behavior when accessing the key as a property. You can still access the key via the #[] method.
W, [2020-12-29T02:27:48.991625 #2790] WARN -- : You are setting a key that conflicts with a built-in method Hashie::Mash#size defined in Hash. This can cause unexpected behavior when accessing the key as a property. You can still access the key via the #[] method.
E
Error:
ActiveModelSerializers::GrapeTest#test_implicit_formatter_handles_collections:
NoMethodError: undefined method `[]' for nil:NilClass
bin/rails test /home/runner/work/active_model_serializers/active_model_serializers/test/grape_test.rb:185
...............................................................................................................................................
Finished in 2.052241s, 280.6688 runs/s, 473.6285 assertions/s.
576 runs, 972 assertions, 0 failures, 7 errors, 0 skips
rake aborted!
Command failed with status (1): [ruby -w -I"lib:lib:test" -r./test/test_helper.rb -w -I"/home/runner/work/active_model_serializers/active_model_serializers/vendor/bundle/ruby/2.6.0/gems/rake-12.3.3/lib" "/home/runner/work/active_model_serializers/active_model_serializers/vendor/bundle/ruby/2.6.0/gems/rake-12.3.3/lib/rake/rake_test_loader.rb" "test/action_controller/adapter_selector_test.rb" "test/action_controller/explicit_serializer_test.rb" "test/action_controller/json/include_test.rb" "test/action_controller/json_api/deserialization_test.rb" "test/action_controller/json_api/errors_test.rb" "test/action_controller/json_api/fields_test.rb" "test/action_controller/json_api/linked_test.rb" "test/action_controller/json_api/pagination_test.rb" "test/action_controller/json_api/transform_test.rb" "test/action_controller/lookup_proc_test.rb" "test/action_controller/namespace_lookup_test.rb" "test/action_controller/serialization_scope_name_test.rb" "test/action_controller/serialization_test.rb" "test/active_model_serializers/adapter_for_test.rb" "test/active_model_serializers/json_pointer_test.rb" "test/active_model_serializers/logging_test.rb" "test/active_model_serializers/model_test.rb" "test/active_model_serializers/test/schema_test.rb" "test/active_model_serializers/test/serializer_test.rb" "test/active_record_test.rb" "test/adapter/attributes_test.rb" "test/adapter/deprecation_test.rb" "test/adapter/json/belongs_to_test.rb" "test/adapter/json/collection_test.rb" "test/adapter/json/fields_test.rb" "test/adapter/json/has_many_test.rb" "test/adapter/json/transform_test.rb" "test/adapter/json_api/belongs_to_test.rb" "test/adapter/json_api/collection_test.rb" "test/adapter/json_api/errors_test.rb" "test/adapter/json_api/fields_test.rb" "test/adapter/json_api/has_many_explicit_serializer_test.rb" "test/adapter/json_api/has_many_test.rb" "test/adapter/json_api/has_one_test.rb" "test/adapter/json_api/include_data_if_sideloaded_test.rb" "test/adapter/json_api/json_api_test.rb" "test/adapter/json_api/linked_test.rb" "test/adapter/json_api/links_test.rb" "test/adapter/json_api/pagination_links_test.rb" "test/adapter/json_api/parse_test.rb" "test/adapter/json_api/relationship_test.rb" "test/adapter/json_api/resource_meta_test.rb" "test/adapter/json_api/toplevel_jsonapi_test.rb" "test/adapter/json_api/transform_test.rb" "test/adapter/json_api/type_test.rb" "test/adapter/json_test.rb" "test/adapter/null_test.rb" "test/adapter/polymorphic_test.rb" "test/adapter_test.rb" "test/array_serializer_test.rb" "test/cache_test.rb" "test/collection_serializer_test.rb" "test/generators/scaffold_controller_generator_test.rb" "test/generators/serializer_generator_test.rb" "test/grape_test.rb" "test/lint_test.rb" "test/logger_test.rb" "test/poro_test.rb" "test/serializable_resource_test.rb" "test/serializers/association_macros_test.rb" "test/serializers/associations_test.rb" "test/serializers/attribute_test.rb" "test/serializers/attributes_test.rb" "test/serializers/configuration_test.rb" "test/serializers/fieldset_test.rb" "test/serializers/meta_test.rb" "test/serializers/options_test.rb" "test/serializers/read_attribute_for_serialization_test.rb" "test/serializers/reflection_test.rb" "test/serializers/root_test.rb" "test/serializers/serialization_test.rb" "test/serializers/serializer_for_test.rb" "test/serializers/serializer_for_with_namespace_test.rb" ]
/home/runner/work/active_model_serializers/active_model_serializers/vendor/bundle/ruby/2.6.0/gems/rake-12.3.3/exe/rake:27:in `<top (required)>'
/opt/hostedtoolcache/Ruby/2.6.6/x64/bin/bundle:23:in `load'
/opt/hostedtoolcache/Ruby/2.6.6/x64/bin/bundle:23:in `<main>'
Tasks: TOP => default => test
(See full trace by running task with --trace)
Error: Process completed with exit code 1.
```
* Loosen pry, pry-byebug depencency
```
Resolving dependencies...
byebug-9.1.0 requires ruby version >= 2.2.0, which is
incompatible with the current version, ruby 2.1.10p492
```
* Adjust nokogiri version constraint for CI
Update appveyor Ruby to 2.3 to work around:
```
Gem::InstallError: nokogiri requires Ruby version < 2.5, >= 2.2.
An error occurred while installing nokogiri (1.8.0), and Bundler cannot continue.
Make sure that `gem install nokogiri -v '1.8.0'` succeeds before bundling.
```
and not 2.4 since:
https://ci.appveyor.com/project/bf4/active-model-serializers/build/1.0.1052-fix_ci/job/0q3itabsnvnxr83u
```
nokogiri-1.6.8.1-x86-mingw32 requires ruby version < 2.4, which is incompatible with the current version, ruby 2.4.1p111
```
* Include rails gem in Gemfile
(For Rails5)
In Rails5, checking for Rails::Railtie is better
* Rails5 test env requires Rails.application.class.name
rails-42d09f6b49da/railties/lib/rails/application.rb
```ruby
def secret_key_base
if Rails.env.test? || Rails.env.development?
Digest::MD5.hexdigest self.class.name
```
* Reformat exclude matrix to be easier to read
* Simplify jruby-travis config per rails/rails
* Organize .travis.yml per rails/rails
* Allow JRuby failure on Rails 5+; try rails-5 db adapter branch
https://github.com/jruby/activerecord-jdbc-adapter/issues/708
```
uninitialized constant ActiveRecord::ConnectionAdapters::Column::Format
```
see https://travis-ci.org/rails-api/active_model_serializers/jobs/277112008
