Add pipeline lists to GraphQL

This adds Keyset pagination to GraphQL lists. PoC for that is
pipelines on merge requests and projects.

When paginating a list, the base-64 encoded id of the ordering
field (in most cases the primary key) can be passed in the `before` or
`after` GraphQL argument.

7 files changed, 131 insertions, 1 deletions

diff --git a/spec/graphql/gitlab_schema_spec.rb b/spec/graphql/gitlab_schema_spec.rb
index b892f6b44ed..515bbe78cb7 100644
--- a/spec/graphql/gitlab_schema_spec.rb
+++ b/spec/graphql/gitlab_schema_spec.rb
@@ -27,6 +27,12 @@ describe GitlabSchema do
     expect(described_class.query).to eq(::Types::QueryType.to_graphql)
   end
 
+  it 'paginates active record relations using `Gitlab::Graphql::Connections::KeysetConnection`' do
+    connection = GraphQL::Relay::BaseConnection::CONNECTION_IMPLEMENTATIONS[ActiveRecord::Relation.name]
+
+    expect(connection).to eq(Gitlab::Graphql::Connections::KeysetConnection)
+  end
+
   def field_instrumenters
     described_class.instrumenters[:field]
   end
diff --git a/spec/graphql/resolvers/concerns/resolves_pipelines_spec.rb b/spec/graphql/resolvers/concerns/resolves_pipelines_spec.rb
new file mode 100644
index 00000000000..ea7159eacf9
--- /dev/null
+++ b/spec/graphql/resolvers/concerns/resolves_pipelines_spec.rb
@@ -0,0 +1,52 @@
+require 'spec_helper'
+
+describe ResolvesPipelines do
+  include GraphqlHelpers
+
+  subject(:resolver) do
+    Class.new(Resolvers::BaseResolver) do
+      include ResolvesPipelines
+
+      def resolve(**args)
+        resolve_pipelines(object, args)
+      end
+    end
+  end
+
+  let(:current_user) { create(:user) }
+  set(:project) { create(:project, :private) }
+  set(:pipeline) { create(:ci_pipeline, project: project) }
+  set(:failed_pipeline) { create(:ci_pipeline, :failed, project: project) }
+  set(:ref_pipeline) { create(:ci_pipeline, project: project, ref: 'awesome-feature') }
+  set(:sha_pipeline) { create(:ci_pipeline, project: project, sha: 'deadbeef') }
+
+  before do
+    project.add_developer(current_user)
+  end
+
+  it { is_expected.to have_graphql_arguments(:status, :ref, :sha) }
+
+  it 'finds all pipelines' do
+    expect(resolve_pipelines).to contain_exactly(pipeline, failed_pipeline, ref_pipeline, sha_pipeline)
+  end
+
+  it 'allows filtering by status' do
+    expect(resolve_pipelines(status: 'failed')).to contain_exactly(failed_pipeline)
+  end
+
+  it 'allows filtering by ref' do
+    expect(resolve_pipelines(ref: 'awesome-feature')).to contain_exactly(ref_pipeline)
+  end
+
+  it 'allows filtering by sha' do
+    expect(resolve_pipelines(sha: 'deadbeef')).to contain_exactly(sha_pipeline)
+  end
+
+  it 'does not return any pipelines if the user does not have access' do
+    expect(resolve_pipelines({}, {})).to be_empty
+  end
+
+  def resolve_pipelines(args = {}, context = { current_user: current_user })
+    resolve(resolver, obj: project, args: args, ctx: context)
+  end
+end
diff --git a/spec/graphql/resolvers/merge_request_pipelines_resolver_spec.rb b/spec/graphql/resolvers/merge_request_pipelines_resolver_spec.rb
new file mode 100644
index 00000000000..09b17bf6fc9
--- /dev/null
+++ b/spec/graphql/resolvers/merge_request_pipelines_resolver_spec.rb
@@ -0,0 +1,30 @@
+require 'spec_helper'
+
+describe Resolvers::MergeRequestPipelinesResolver do
+  include GraphqlHelpers
+
+  set(:merge_request) { create(:merge_request) }
+  set(:pipeline) do
+    create(
+      :ci_pipeline,
+      project: merge_request.source_project,
+      ref: merge_request.source_branch,
+      sha: merge_request.diff_head_sha
+    )
+  end
+  set(:other_project_pipeline) { create(:ci_pipeline, project: merge_request.source_project) }
+  set(:other_pipeline) { create(:ci_pipeline) }
+  let(:current_user) { create(:user) }
+
+  before do
+    merge_request.project.add_developer(current_user)
+  end
+
+  def resolve_pipelines
+    resolve(described_class, obj: merge_request, ctx: { current_user: current_user })
+  end
+
+  it 'resolves only MRs for the passed merge request' do
+    expect(resolve_pipelines).to contain_exactly(pipeline)
+  end
+end
diff --git a/spec/graphql/resolvers/project_pipelines_resolver_spec.rb b/spec/graphql/resolvers/project_pipelines_resolver_spec.rb
new file mode 100644
index 00000000000..407ca2f9d78
--- /dev/null
+++ b/spec/graphql/resolvers/project_pipelines_resolver_spec.rb
@@ -0,0 +1,22 @@
+require 'spec_helper'
+
+describe Resolvers::ProjectPipelinesResolver do
+  include GraphqlHelpers
+
+  set(:project) { create(:project) }
+  set(:pipeline) {  create(:ci_pipeline, project: project) }
+  set(:other_pipeline) { create(:ci_pipeline) }
+  let(:current_user) { create(:user) }
+
+  before do
+    project.add_developer(current_user)
+  end
+
+  def resolve_pipelines
+    resolve(described_class, obj: project, ctx: { current_user: current_user })
+  end
+
+  it 'resolves only MRs for the passed merge request' do
+    expect(resolve_pipelines).to contain_exactly(pipeline)
+  end
+end
diff --git a/spec/graphql/types/ci/pipeline_type_spec.rb b/spec/graphql/types/ci/pipeline_type_spec.rb
new file mode 100644
index 00000000000..ec1c689a4be
--- /dev/null
+++ b/spec/graphql/types/ci/pipeline_type_spec.rb
@@ -0,0 +1,7 @@
+require 'spec_helper'
+
+describe Types::Ci::PipelineType do
+  it { expect(described_class.graphql_name).to eq('Pipeline') }
+
+  it { expect(described_class).to expose_permissions_using(Types::PermissionTypes::Ci::Pipeline) }
+end
diff --git a/spec/graphql/types/merge_request_type_spec.rb b/spec/graphql/types/merge_request_type_spec.rb
index 6e57122867a..c369953e3ea 100644
--- a/spec/graphql/types/merge_request_type_spec.rb
+++ b/spec/graphql/types/merge_request_type_spec.rb
@@ -1,5 +1,16 @@
 require 'spec_helper'
 
-describe Types::MergeRequestType do
+describe GitlabSchema.types['MergeRequest'] do
   it { expect(described_class).to expose_permissions_using(Types::PermissionTypes::MergeRequest) }
+
+  describe 'head pipeline' do
+    it 'has a head pipeline field' do
+      expect(described_class).to have_graphql_field(:head_pipeline)
+    end
+
+    it 'authorizes the field' do
+      expect(described_class.fields['headPipeline'])
+        .to require_graphql_authorizations(:read_pipeline)
+    end
+  end
 end
diff --git a/spec/graphql/types/project_type_spec.rb b/spec/graphql/types/project_type_spec.rb
index 7b5bc335511..49606c397b9 100644
--- a/spec/graphql/types/project_type_spec.rb
+++ b/spec/graphql/types/project_type_spec.rb
@@ -13,4 +13,6 @@ describe GitlabSchema.types['Project'] do
         .to  require_graphql_authorizations(:read_merge_request)
     end
   end
+
+  it { is_expected.to have_graphql_field(:pipelines) }
 end