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Convenient rspec matchers for testing your graphql-ruby API/Schema.


gem 'rspec-graphql_matchers'


The matchers currently supported are:

  • expect(a_graphql_object).to have_a_field(field_name).of_type(valid_type)
  • expect(a_graphql_object).to implement(interface_name, ...)
  • expect(a_mutation_type).to have_a_return_field(field_name).returning(valid_type)
  • expect(a_mutation_type).to have_an_input_field(field_name).of_type(valid_type)
  • expect(a_field).to be_of_type(valid_type)
  • expect(an_input).to accept_argument(argument_name).of_type(valid_type)

Where a valid type for the expectation is either:

  • A reference to the actual type you expect;
  • [Recommended] A String representation of a type: "String!", "Int!", "[String]!" (note the exclamation mark at the end, as required by the GraphQL specs.

For objects defined with the legacy #define api, testing :property, :hash_key and metadata is also possible by chaining .with_property, .with_hash_key and .with_metadata. For example:

  • expect(a_graphql_object).to have_a_field(field_name).with_property(property_name).with_metadata(metadata_hash)
  • expect(a_graphql_object).to have_a_field(field_name).with_hash_key(hash_key)


Given a GraphQL object defined as

class PostType < GraphQL::Schema::Object
  graphql_name "Post"
  description "A blog post"

  implements GraphQL::Relay::Node.interface

  field :id, ID, null: false
  field :comments, [String], null: false
  field :isPublished, Boolean, null: true
  field :published, Boolean, null: false, deprecation_reason: 'Use isPublished instead'

  field :subposts, PostType, null: true do
    argument :filter, types.String, required: false
    argument :id, types.ID, required: false
    argument :isPublished, types.Boolean, required: false

1) Test your type defines the correct fields:

describe PostType do
  subject { described_class }

  it { have_field(:id).of_type(!types.ID) }
  it { have_field(:comments).of_type("[String!]!") }
  it { have_field(:isPublished).of_type("Boolean") }

  # Check a field is deprecated
  it { have_field(:published).with_deprecation_reason }
  it { have_field(:published).with_deprecation_reason('Use isPublished instead') }
  it { is_expected.not_to have_field(:published).with_deprecation_reason('Wrong reason') }
  it { is_expected.not_to have_field(:isPublished).with_deprecation_reason }

  # The gem automatically converts field names to CamelCase, so this will
  # pass even though the field was defined as field :isPublished
  it { have_field(:is_published).of_type("Boolean") }

2) Test a specific field type with be_of_type matcher:

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

    it { be_of_type('ID!') }
    it { is_expected.not_to be_of_type('Float!') }

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

    it { be_of_type('Post') }

3) For objects defined using the legacy #define api, you can also use with_property, with_hash_key and with_metadata:

PostTypeWithDefineApi = GraphQL::ObjectType.define do
  name "DefinedPost"

  interfaces [GraphQL::Relay::Node.interface]

  field :id, !types.ID, property: :post_id
  field :comments, !types[types.String], hash_key: :post_comments
  field :isPublished, admin_only: true

describe PostTypeWithDefineApi do
  it { have_a_field(:id).of_type('ID!').with_property(:post_id) }
  it { have_a_field(:comments).with_hash_key(:post_comments) }
  it { have_a_field(:isPublished).(admin_only: true) }

4) Test the arguments accepted by a field with accept_argument matcher:

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

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

    it { is_expected.not_to accept_argument(:weirdo) }

    # The gem automatically converts argument names to CamelCase, so this will
    # pass even though the argument was defined as :isPublished
    it { accept_argument(:is_published).of_type("Boolean") }

5) Test an object's interface implementations:

describe PostType do
  subject { described_class }

  it 'implements interface Node' do
    expect(subject).to implement('Node')

  # Accepts arguments as an array and type objects directly
  it { implement(GraphQL::Relay::Node.interface) }
  it { is_expected.not_to implement('OtherInterface') }

6) Using camelize: false on field names

By default the graphql gem camelizes field names. This gem deals with it transparently:

class ObjectMessingWithCamelsAndSnakesType < GraphQL::Schema::Object
  graphql_name 'ObjectMessingWithCamelsAndSnakes'

  implements GraphQL::Relay::Node.interface

  field :me_gusta_los_camellos, ID, null: false

  # note the camelize: false
  field :prefiero_serpientes, ID, null: false, camelize: false

The following specs demonstrate the current behavior of the gem regarding fields:

describe ObjectMessingWithCamelsAndSnakesType do
  subject { described_class }

  # For a field name that was automatically camelized, you can add expectations
  # against both versions and we handle it transparently:
  it { have_a_field(:meGustaLosCamellos) }
  it { have_a_field(:me_gusta_los_camellos) }

  # However, when using camelize: false, you have to use the exact case of the field definition:
  it { have_a_field(:prefiero_serpientes) }
  it { is_expected.not_to have_a_field(:prefieroSerpientes) } # Note we're using `not_to`

This behaviour is currently active only on field name matching. PRs are welcome to reproduce it to arguments as well.


  • New matchers!


  • 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.


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