Rspec::GraphqlMatchers

Convenient rspec matchers for testing your (GraphQL)[https://github.com/rmosolgo/graphql-ruby] API/Schema.

Installation

gem 'rspec-graphql_matchers'

Usage

The two matchers currently supported are:

• be_of_type(a_graphql_type_identifier)
• accept_arguments(hash_of_arg_names_and_type_identifiers)

Where a type identifier is either:

• A GraphQL type object (ex: types.String, !types.Int, types[types.Int])
• A String representation of a type: "String!", "Int!", "[String]!"

Examples

Given a GraphQL type defined as such

PostType = GraphQL::ObjectType.define do
  name "Post"
  description "A blog post"

  field :id, !types.ID

  field :comments, !types[types.String]

  field :subposts, PostType do
    type !PostType

    argument :filter, types.String
    argument :id, types.ID
  end
end

1) Test the field types with be_of_type matcher:

describe PostType do
  describe 'id' do
    subject { PostType.fields['id'] }

    # These will match
    it { is_expected.to be_of_type('ID!') }

    # While 'Float!' will not match
    it { is_expected.not_to be_of_type('Float!') }
  end

  describe 'subposts' do
    subject { PostType.fields['subposts'] }

    # You can use your type object directly when building expectations
    it 'has type PostType' do
      expect(subject).to be_of_type(!PostType)
    end

    # Or as usual, a literal String
    it { is_expected.to be_of_type('Post!') }
  end
end

Keep in mind that when using strings as type expectation you have to use the type name (Post) and not the constant name (PostType).

Using your type objects directly has the advantage that if you decide to rename the type your specs won't break, as they would had you hardcoded the type name as a String.

You can also use the built-in GraphQL scalar types:

# ensure you have the GraphQL type definer available in your tests
types = GraphQL::Define::TypeDefiner.instance

describe PostType do
  describe 'comments' do
    subject { PostType.fields['comments'] }
    it { is_expected.to be_of_type(!types[types.String]) }
    it { is_expected.to be_of_type('[String]!') }
  end
end

Having to define types everywhere is quite annoying. If you prefer, you can just include RSpec::GraphqlMatchers::TypesHelper once (for example in your spec_helper.rb, but not within a RSpec.configure block) and the types shortcut will be available globally (ouch!) for your tests. Use at your own risk.

2) Test the arguments accepted by a field with accept_arguments matcher:

Testing arguments use the accept_arguments matcher passing a hash where keys represent the attribute name and values respresent the attribute type.

describe PostType do
  describe 'subposts' do
    subject { PostType.fields['subposts'] }

    let(:a_whole_bunch_of_args) do
      { filter: 'String', id: types.Int, pippo: 'Float', posts: PostType }
    end

    it 'accepts a filter and an id argument, of types String and ID' do
      expect(subject).to accept_arguments(filter: types.String, id: types.ID)
    end

    # You can also test if a field does not accept args. Not quite useful :D.
    it { is_expected.not_to accept_arguments(a_whole_bunch_of_args) }
  end
end

The spec will pass only if all attributes/types specified in the hash are defined on the field. Type specification follows the same rules from be_of_type matcher.

For better fluency, accept_arguments is always available in singular form, as accept_argument.

Contributing

• Send Bug reports, suggestions or any general question through the Issue tracker. Think of another matcher that could be useful? This is the place to ask, or...
• Pull requests are welcome through the usual procedure: fork the project, commit your changes and open the PR.

This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

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