Add CI template field to project GraphQL type

Changelog: added

app/graphql/resolvers/ci/template_resolver.rb

+# frozen_string_literal: true
+
+module Resolvers
+  module Ci
+    class TemplateResolver < BaseResolver
+      type Types::Ci::TemplateType, null: true
+
+      argument :name, GraphQL::STRING_TYPE, required: true,
+        description: 'Name of the template to search for.'
+
+      alias_method :project, :object
+
+      def resolve(name: nil)
+        ::TemplateFinder.new(:gitlab_ci_ymls, project, name: name).execute
+      end
+    end
+  end
+end

app/graphql/types/ci/template_type.rb

+# frozen_string_literal: true
+
+module Types
+  module Ci
+    # rubocop: disable Graphql/AuthorizeTypes
+    class TemplateType < BaseObject
+      graphql_name 'CiTemplate'
+
+      field :name, GraphQL::STRING_TYPE, null: false,
+        description: 'Name of the CI template.'
+      field :content, GraphQL::STRING_TYPE, null: false,
+        description: 'Contents of the CI template.'
+    end
+  end
+end

app/graphql/types/project_type.rb

@@ -337,6 +337,10 @@ module Types
           description: 'Pipeline analytics.',
           resolver: Resolvers::ProjectPipelineStatisticsResolver
 
+    field :ci_template, Types::Ci::TemplateType, null: true,
+          description: 'Find a single CI template by name.',
+          resolver: Resolvers::Ci::TemplateResolver
+
     def label(title:)
       BatchLoader::GraphQL.for(title).batch(key: project) do |titles, loader, args|
         LabelsFinder

spec/graphql/resolvers/ci/template_resolver_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Resolvers::Ci::TemplateResolver do
+  include GraphqlHelpers
+
+  describe '#resolve' do
+    let(:user) { create(:user) }
+    let(:project) { create(:project) }
+
+    subject(:resolve_subject) { resolve(described_class, obj: project, ctx: { current_user: user }, args: { name: template_name }) }
+
+    context 'when template exists' do
+      let(:template_name) { 'Android' }
+
+      it 'returns the found template' do
+        found_template = resolve_subject
+
+        expect(found_template).to be_an_instance_of(Gitlab::Template::GitlabCiYmlTemplate)
+        expect(found_template.name).to eq('Android')
+      end
+    end
+
+    context 'when template does not exist' do
+      let(:template_name) { 'invalidname' }
+
+      it 'returns nil' do
+        expect(resolve_subject).to eq(nil)
+      end
+    end
+  end
+end

spec/graphql/types/ci/template_type_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Types::Ci::TemplateType do
+  specify { expect(described_class.graphql_name).to eq('CiTemplate') }
+
+  it 'exposes the expected fields' do
+    expected_fields = %i[
+      name
+      content
+    ]
+
+    expect(described_class).to have_graphql_fields(*expected_fields)
+  end
+end

spec/graphql/types/project_type_spec.rb

@@ -32,6 +32,7 @@ RSpec.describe GitlabSchema.types['Project'] do
       issue_status_counts terraform_states alert_management_integrations
       container_repositories container_repositories_count
       pipeline_analytics squash_read_only sast_ci_configuration
+      ci_template
     ]
 
     expect(described_class).to include_graphql_fields(*expected_fields)
@@ -379,4 +380,11 @@ RSpec.describe GitlabSchema.types['Project'] do
     it { is_expected.to have_graphql_type(Types::Ci::JobType.connection_type) }
     it { is_expected.to have_graphql_arguments(:statuses) }
   end
+
+  describe 'ci_template field' do
+    subject { described_class.fields['ciTemplate'] }
+
+    it { is_expected.to have_graphql_type(Types::Ci::TemplateType) }
+    it { is_expected.to have_graphql_arguments(:name) }
+  end
 end

spec/requests/api/graphql/ci/template_spec.rb

+# frozen_string_literal: true
+require 'spec_helper'
+
+RSpec.describe 'Querying CI template' do
+  include GraphqlHelpers
+
+  let_it_be(:project) { create(:project, :public) }
+  let_it_be(:user) { create(:user) }
+
+  let(:query) do
+    <<~QUERY
+    {
+      project(fullPath: "#{project.full_path}") {
+        name
+        ciTemplate(name: "#{template_name}") {
+          name
+          content
+        }
+      }
+    }
+    QUERY
+  end
+
+  before do
+    post_graphql(query, current_user: user)
+  end
+
+  context 'when the template exists' do
+    let(:template_name) { 'Android' }
+
+    it_behaves_like 'a working graphql query'
+
+    it 'returns correct data' do
+      expect(graphql_data.dig('project', 'ciTemplate', 'name')).to eq(template_name)
+      expect(graphql_data.dig('project', 'ciTemplate', 'content')).not_to be_blank
+    end
+  end
+
+  context 'when the template does not exist' do
+    let(:template_name) { 'doesnotexist' }
+
+    it_behaves_like 'a working graphql query'
+
+    it 'returns correct data' do
+      expect(graphql_data.dig('project', 'ciTemplate')).to eq(nil)
+    end
+  end
+end