Skooma – Sugar for your APIs

Skooma is a Ruby library for validating API implementations against OpenAPI documents.

Features

• Supports OpenAPI 3.1.0
• Supports OpenAPI document validation
• Supports request/response validations against OpenAPI document
• Includes RSpec and Minitest helpers

Learn more

• Let there be docs! A documentation-first approach to Rails API development

Installation

Install the gem and add to the application's Gemfile by executing:

$ bundle add skooma

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install skooma

Usage

Skooma provides rspec and minitest helpers for validating OpenAPI documents and requests/responses against them. Skooma helpers are designed to be used with rails request specs or rack-test.

RSpec

Configuration

# spec/rails_helper.rb

RSpec.configure do |config|
  # ...
  path_to_openapi = Rails.root.join("docs", "openapi.yml")
  config.include Skooma::RSpec[path_to_openapi], type: :request

  # OR pass path_prefix option if your API is mounted under a prefix:
  config.include Skooma::RSpec[path_to_openapi, path_prefix: "/internal/api"], type: :request

  # To enable coverage, pass `coverage: :report` option,
  # and to raise an error when an operation is not covered, pass `coverage: :strict` option:
  config.include Skooma::RSpec[path_to_openapi, coverage: :report], type: :request
end

Validate OpenAPI document

# spec/openapi_spec.rb

require "rails_helper"

describe "OpenAPI document", type: :request do
  subject(:schema) { skooma_openapi_schema }

  it { is_expected.to be_valid_document }
end

Validate request

# spec/requests/feed_spec.rb

require "rails_helper"

describe "/animals/:animal_id/feed" do  
  let(:animal) { create(:animal, :unicorn) }
  
  describe "POST" do
    subject { post "/animals/#{animal.id}/feed", body:, as: :json }
    
    let(:body) { {food: "apple", quantity: 3} }

    it { is_expected.to conform_schema(200) }

    context "with wrong food type" do
      let(:body) { {food: "wood", quantity: 1} }
    
      it { is_expected.to conform_schema(422) }
    end
  end
end

# Validation Result:
#
#  {"valid"=>false,
#   "instanceLocation"=>"",
#   "keywordLocation"=>"",
#   "absoluteKeywordLocation"=>"urn:uuid:1b4b39eb-9b93-4cc1-b6ac-32a25d9bff50#",
#   "errors"=>
#     [{"instanceLocation"=>"",
#       "keywordLocation"=>
#         "/paths/~1animals~1{animalId}~1feed/post/responses/200"/
#           "/content/application~1json/schema/required",
#       "error"=>
#         "The object is missing required properties"/
#           " [\"animalId\", \"food\", \"amount\"]"}]}

Minitest

Configuration

# test/test_helper.rb
path_to_openapi = Rails.root.join("docs", "openapi.yml")
ActionDispatch::IntegrationTest.include Skooma::Minitest[path_to_openapi]

# OR pass path_prefix option if your API is mounted under a prefix:
ActionDispatch::IntegrationTest.include Skooma::Minitest[path_to_openapi, path_prefix: "/internal/api"], type: :request

# To enable coverage, pass `coverage: :report` option,
# and to raise an error when an operation is not covered, pass `coverage: :strict` option:
ActionDispatch::IntegrationTest.include Skooma::Minitest[path_to_openapi, coverage: :report], type: :request

Validate OpenAPI document

# test/openapi_test.rb

require "test_helper"

class OpenapiTest < ActionDispatch::IntegrationTest
  test "is valid OpenAPI document" do
    assert_is_valid_document(skooma_openapi_schema)
  end
end

Validate request

# test/integration/items_test.rb

require "test_helper"

class ItemsTest < ActionDispatch::IntegrationTest
  test "GET /" do
    get "/"
    assert_conform_schema(200)
  end

  test "POST / conforms to schema with 201 response code" do
    post "/", params: {foo: "bar"}, as: :json
    assert_conform_schema(201)
  end

  test "POST / conforms to schema with 400 response code" do
    post "/", params: {foo: "baz"}, as: :json
    assert_conform_response_schema(400)
  end
end

Alternatives

• openapi_first
• committee

Feature plans

• Full support for external $refs
• Full OpenAPI 3.1.0 support:
  • respect style and explode keywords
  • xml
• Callbacks and webhooks validations
• Example validations
• Ability to plug in custom X-*** keyword classes

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/skryukov/skooma.

License

The gem is available as open source under the terms of the MIT License.