Add a IncidentManagement::OncallScheduleResolver

Add a GraphQL resolver for on-call schedules

ee/app/graphql/ee/types/project_type.rb

@@ -151,7 +151,8 @@ module EE
         field :incident_management_oncall_schedules,
               ::Types::IncidentManagement::OncallScheduleType.connection_type,
               null: true,
-              description: 'Incident Management On-call schedules of the project'
+              description: 'Incident Management On-call schedules of the project',
+              resolver: ::Resolvers::IncidentManagement::OncallScheduleResolver
 
         def self.sast_ci_configuration(project)
           ::Security::CiConfiguration::SastParserService.new(project).configuration

ee/app/graphql/resolvers/incident_management/oncall_schedule_resolver.rb

+# frozen_string_literal: true
+
+module Resolvers
+  module IncidentManagement
+    class OncallScheduleResolver < BaseResolver
+      alias_method :project, :synchronized_object
+
+      type Types::IncidentManagement::OncallScheduleType.connection_type, null: true
+
+      def resolve(**args)
+        return [] unless Ability.allowed?(current_user, :read_incident_management_oncall_schedule, project)
+
+
+        project.incident_management_oncall_schedules
+      end
+    end
+  end
+end

ee/spec/graphql/resolvers/incident_management/oncall_schedule_resolver_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Resolvers::IncidentManagement::OncallScheduleResolver do
+  include GraphqlHelpers
+
+  let_it_be(:current_user) { create(:user) }
+  let_it_be(:project) { create(:project) }
+  let_it_be(:oncall_schedule) { create(:incident_management_oncall_schedule, project: project) }
+
+  subject { sync(resolve_oncall_schedules) }
+
+  specify do
+    expect(described_class).to have_nullable_graphql_type(Types::IncidentManagement::OncallScheduleType.connection_type)
+  end
+
+  context 'user does not have permissions' do
+    it { is_expected.to eq(IncidentManagement::OncallSchedule.none) }
+  end
+
+  context 'user has permissions' do
+    before do
+      project.add_maintainer(current_user)
+    end
+
+    it { is_expected.to contain_exactly(oncall_schedule) }
+
+    # TODO: check feature flag
+    # TODO: check license "Premium"
+  end
+
+  private
+
+  def resolve_oncall_schedules(args = {}, context = { current_user: current_user })
+    resolve(described_class, obj: project, args: args, ctx: context)
+  end
+end

ee/spec/requests/api/graphql/project/incident_management/oncall_schedules_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'getting Incident Management on-call schedules' do
+  include GraphqlHelpers
+
+  let_it_be(:project) { create(:project) }
+  let_it_be(:current_user) { create(:user) }
+
+  let(:params) { {} }
+
+  let(:fields) do
+    <<~QUERY
+      nodes {
+        #{all_graphql_fields_for('IncidentManagementOncallSchedule')}
+      }
+    QUERY
+  end
+
+  let(:query) do
+    graphql_query_for(
+      'project',
+      { 'fullPath' => project.full_path },
+      query_graphql_field('incidentManagementOncallSchedules', {}, fields)
+    )
+  end
+
+  let(:oncall_schedules) { graphql_data.dig('project', 'incidentManagementOncallSchedules', 'nodes') }
+
+  context 'without project permissions' do
+    let(:user) { create(:user) }
+
+    before do
+      post_graphql(query, current_user: current_user)
+    end
+
+    it_behaves_like 'a working graphql query'
+
+    it { expect(oncall_schedules).to be_nil }
+  end
+
+  context 'with project permissions' do
+    before do
+      project.add_maintainer(current_user)
+    end
+
+    context 'without on-call schedules' do
+      before do
+        post_graphql(query, current_user: current_user)
+      end
+
+      it_behaves_like 'a working graphql query'
+
+      it { expect(oncall_schedules).to be_empty }
+    end
+
+    context 'with on-call schedules' do
+      let!(:oncall_schedule) { create(:incident_management_oncall_schedule, project: project) }
+      let(:last_oncall_schedule) { oncall_schedules.last }
+
+      before do
+        post_graphql(query, current_user: current_user)
+      end
+
+      it_behaves_like 'a working graphql query'
+
+      it 'returns the correct properties of the on-call schedule' do
+        expect(last_oncall_schedule).to include(
+          'iid' => oncall_schedule.iid.to_s,
+          'name' => oncall_schedule.name,
+          'description' => oncall_schedule.description,
+          'timezone' => oncall_schedule.timezone
+        )
+      end
+    end
+  end
+end