Merge branch 'bvl-graphql-start-34754' into 'master'

GraphQL setup: Basic Project and Merge request endpoint

Closes #34754

See merge request gitlab-org/gitlab-ce!19008

14 files changed, 517 insertions, 5 deletions

diff --git a/spec/controllers/graphql_controller_spec.rb b/spec/controllers/graphql_controller_spec.rb
new file mode 100644
index 00000000000..1449036e148
--- /dev/null
+++ b/spec/controllers/graphql_controller_spec.rb
@@ -0,0 +1,69 @@
+require 'spec_helper'
+
+describe GraphqlController do
+  describe 'execute' do
+    let(:user) { nil }
+
+    before do
+      sign_in(user) if user
+
+      run_test_query!
+    end
+
+    subject { query_response }
+
+    context 'graphql is disabled by feature flag' do
+      let(:user) { nil }
+
+      before do
+        stub_feature_flags(graphql: false)
+      end
+
+      it 'returns 404' do
+        run_test_query!
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+
+    context 'signed out' do
+      let(:user) { nil }
+
+      it 'runs the query with current_user: nil' do
+        is_expected.to eq('echo' => 'nil says: test success')
+      end
+    end
+
+    context 'signed in' do
+      let(:user) { create(:user, username: 'Simon') }
+
+      it 'runs the query with current_user set' do
+        is_expected.to eq('echo' => '"Simon" says: test success')
+      end
+    end
+
+    context 'invalid variables' do
+      it 'returns an error' do
+        run_test_query!(variables: "This is not JSON")
+
+        expect(response).to have_gitlab_http_status(422)
+        expect(json_response['errors'].first['message']).not_to be_nil
+      end
+    end
+  end
+
+  # Chosen to exercise all the moving parts in GraphqlController#execute
+  def run_test_query!(variables: { 'text' => 'test success' })
+    query = <<~QUERY
+      query Echo($text: String) {
+        echo(text: $text)
+      }
+    QUERY
+
+    post :execute, query: query, operationName: 'Echo', variables: variables
+  end
+
+  def query_response
+    json_response['data']
+  end
+end
diff --git a/spec/graphql/gitlab_schema_spec.rb b/spec/graphql/gitlab_schema_spec.rb
new file mode 100644
index 00000000000..b892f6b44ed
--- /dev/null
+++ b/spec/graphql/gitlab_schema_spec.rb
@@ -0,0 +1,33 @@
+require 'spec_helper'
+
+describe GitlabSchema do
+  it 'uses batch loading' do
+    expect(field_instrumenters).to include(BatchLoader::GraphQL)
+  end
+
+  it 'enables the preload instrumenter' do
+    expect(field_instrumenters).to include(BatchLoader::GraphQL)
+  end
+
+  it 'enables the authorization instrumenter' do
+    expect(field_instrumenters).to include(instance_of(::Gitlab::Graphql::Authorize::Instrumentation))
+  end
+
+  it 'enables using presenters' do
+    expect(field_instrumenters).to include(instance_of(::Gitlab::Graphql::Present::Instrumentation))
+  end
+
+  it 'has the base mutation' do
+    pending('Adding an empty mutation breaks the documentation explorer')
+
+    expect(described_class.mutation).to eq(::Types::MutationType.to_graphql)
+  end
+
+  it 'has the base query' do
+    expect(described_class.query).to eq(::Types::QueryType.to_graphql)
+  end
+
+  def field_instrumenters
+    described_class.instrumenters[:field]
+  end
+end
diff --git a/spec/graphql/resolvers/merge_request_resolver_spec.rb b/spec/graphql/resolvers/merge_request_resolver_spec.rb
new file mode 100644
index 00000000000..af015533209
--- /dev/null
+++ b/spec/graphql/resolvers/merge_request_resolver_spec.rb
@@ -0,0 +1,58 @@
+require 'spec_helper'
+
+describe Resolvers::MergeRequestResolver do
+  include GraphqlHelpers
+
+  set(:project) { create(:project, :repository) }
+  set(:merge_request_1) { create(:merge_request, :simple, source_project: project, target_project: project) }
+  set(:merge_request_2) { create(:merge_request, :rebased, source_project: project, target_project: project) }
+
+  set(:other_project) { create(:project, :repository) }
+  set(:other_merge_request) { create(:merge_request, source_project: other_project, target_project: other_project) }
+
+  let(:full_path) { project.full_path }
+  let(:iid_1) { merge_request_1.iid }
+  let(:iid_2) { merge_request_2.iid }
+
+  let(:other_full_path) { other_project.full_path }
+  let(:other_iid) { other_merge_request.iid }
+
+  describe '#resolve' do
+    it 'batch-resolves merge requests by target project full path and IID' do
+      path = full_path # avoid database query
+
+      result = batch(max_queries: 2) do
+        [resolve_mr(path, iid_1), resolve_mr(path, iid_2)]
+      end
+
+      expect(result).to contain_exactly(merge_request_1, merge_request_2)
+    end
+
+    it 'can batch-resolve merge requests from different projects' do
+      path = project.full_path # avoid database queries
+      other_path = other_full_path
+
+      result = batch(max_queries: 3) do
+        [resolve_mr(path, iid_1), resolve_mr(path, iid_2), resolve_mr(other_path, other_iid)]
+      end
+
+      expect(result).to contain_exactly(merge_request_1, merge_request_2, other_merge_request)
+    end
+
+    it 'resolves an unknown iid to nil' do
+      result = batch { resolve_mr(full_path, -1) }
+
+      expect(result).to be_nil
+    end
+
+    it 'resolves a known iid for an unknown full_path to nil' do
+      result = batch { resolve_mr('unknown/project', iid_1) }
+
+      expect(result).to be_nil
+    end
+  end
+
+  def resolve_mr(full_path, iid)
+    resolve(described_class, args: { full_path: full_path, iid: iid })
+  end
+end
diff --git a/spec/graphql/resolvers/project_resolver_spec.rb b/spec/graphql/resolvers/project_resolver_spec.rb
new file mode 100644
index 00000000000..d4990c6492c
--- /dev/null
+++ b/spec/graphql/resolvers/project_resolver_spec.rb
@@ -0,0 +1,32 @@
+require 'spec_helper'
+
+describe Resolvers::ProjectResolver do
+  include GraphqlHelpers
+
+  set(:project1) { create(:project) }
+  set(:project2) { create(:project) }
+
+  set(:other_project) { create(:project) }
+
+  describe '#resolve' do
+    it 'batch-resolves projects by full path' do
+      paths = [project1.full_path, project2.full_path]
+
+      result = batch(max_queries: 1) do
+        paths.map { |path| resolve_project(path) }
+      end
+
+      expect(result).to contain_exactly(project1, project2)
+    end
+
+    it 'resolves an unknown full_path to nil' do
+      result = batch { resolve_project('unknown/project') }
+
+      expect(result).to be_nil
+    end
+  end
+
+  def resolve_project(full_path)
+    resolve(described_class, args: { full_path: full_path })
+  end
+end
diff --git a/spec/graphql/types/project_type_spec.rb b/spec/graphql/types/project_type_spec.rb
new file mode 100644
index 00000000000..e0f89105b86
--- /dev/null
+++ b/spec/graphql/types/project_type_spec.rb
@@ -0,0 +1,5 @@
+require 'spec_helper'
+
+describe GitlabSchema.types['Project'] do
+  it { expect(described_class.graphql_name).to eq('Project') }
+end
diff --git a/spec/graphql/types/query_type_spec.rb b/spec/graphql/types/query_type_spec.rb
new file mode 100644
index 00000000000..8488252fd59
--- /dev/null
+++ b/spec/graphql/types/query_type_spec.rb
@@ -0,0 +1,37 @@
+require 'spec_helper'
+
+describe GitlabSchema.types['Query'] do
+  it 'is called Query' do
+    expect(described_class.graphql_name).to eq('Query')
+  end
+
+  it { is_expected.to have_graphql_fields(:project, :merge_request, :echo) }
+
+  describe 'project field' do
+    subject { described_class.fields['project'] }
+
+    it 'finds projects by full path' do
+      is_expected.to have_graphql_arguments(:full_path)
+      is_expected.to have_graphql_type(Types::ProjectType)
+      is_expected.to have_graphql_resolver(Resolvers::ProjectResolver)
+    end
+
+    it 'authorizes with read_project' do
+      is_expected.to require_graphql_authorizations(:read_project)
+    end
+  end
+
+  describe 'merge_request field' do
+    subject { described_class.fields['mergeRequest'] }
+
+    it 'finds MRs by project and IID' do
+      is_expected.to have_graphql_arguments(:full_path, :iid)
+      is_expected.to have_graphql_type(Types::MergeRequestType)
+      is_expected.to have_graphql_resolver(Resolvers::MergeRequestResolver)
+    end
+
+    it 'authorizes with read_merge_request' do
+      is_expected.to require_graphql_authorizations(:read_merge_request)
+    end
+  end
+end
diff --git a/spec/graphql/types/time_type_spec.rb b/spec/graphql/types/time_type_spec.rb
new file mode 100644
index 00000000000..4196d9d27d4
--- /dev/null
+++ b/spec/graphql/types/time_type_spec.rb
@@ -0,0 +1,16 @@
+require 'spec_helper'
+
+describe GitlabSchema.types['Time'] do
+  let(:iso) { "2018-06-04T15:23:50+02:00" }
+  let(:time) { Time.parse(iso) }
+
+  it { expect(described_class.graphql_name).to eq('Time') }
+
+  it 'coerces Time object into ISO 8601' do
+    expect(described_class.coerce_isolated_result(time)).to eq(iso)
+  end
+
+  it 'coerces an ISO-time into Time object' do
+    expect(described_class.coerce_isolated_input(iso)).to eq(time)
+  end
+end
diff --git a/spec/lib/gitlab/path_regex_spec.rb b/spec/lib/gitlab/path_regex_spec.rb
index a40330d853f..e90e0aba0a4 100644
--- a/spec/lib/gitlab/path_regex_spec.rb
+++ b/spec/lib/gitlab/path_regex_spec.rb
@@ -90,11 +90,13 @@ describe Gitlab::PathRegex do
   let(:routes_not_starting_in_wildcard) { routes_without_format.select { |p| p !~ %r{^/[:*]} } }
 
   let(:top_level_words) do
-    words = routes_not_starting_in_wildcard.map do |route|
-      route.split('/')[1]
-    end.compact
-
-    (words + ee_top_level_words + files_in_public + Array(API::API.prefix.to_s)).uniq
+    routes_not_starting_in_wildcard
+      .map { |route| route.split('/')[1] }
+      .concat(ee_top_level_words)
+      .concat(files_in_public)
+      .concat(Array(API::API.prefix.to_s))
+      .compact
+      .uniq
   end
 
   let(:ee_top_level_words) do
diff --git a/spec/requests/api/graphql/merge_request_query_spec.rb b/spec/requests/api/graphql/merge_request_query_spec.rb
new file mode 100644
index 00000000000..12b1d5d18a2
--- /dev/null
+++ b/spec/requests/api/graphql/merge_request_query_spec.rb
@@ -0,0 +1,49 @@
+require 'spec_helper'
+
+describe 'getting merge request information' do
+  include GraphqlHelpers
+
+  let(:project) { create(:project, :repository) }
+  let(:merge_request) { create(:merge_request, source_project: project) }
+  let(:current_user) { create(:user) }
+
+  let(:query) do
+    attributes = {
+      'fullPath' => merge_request.project.full_path,
+      'iid' => merge_request.iid
+    }
+    graphql_query_for('mergeRequest',  attributes)
+  end
+
+  context 'when the user has access to the merge request' do
+    before do
+      project.add_developer(current_user)
+      post_graphql(query, current_user: current_user)
+    end
+
+    it 'returns the merge request' do
+      expect(graphql_data['mergeRequest']).not_to be_nil
+    end
+
+    # This is a field coming from the `MergeRequestPresenter`
+    it 'includes a web_url' do
+      expect(graphql_data['mergeRequest']['webUrl']).to be_present
+    end
+
+    it_behaves_like 'a working graphql query'
+  end
+
+  context 'when the user does not have access to the merge request' do
+    before do
+      post_graphql(query, current_user: current_user)
+    end
+
+    it 'returns an empty field' do
+      post_graphql(query, current_user: current_user)
+
+      expect(graphql_data['mergeRequest']).to be_nil
+    end
+
+    it_behaves_like 'a working graphql query'
+  end
+end
diff --git a/spec/requests/api/graphql/project_query_spec.rb b/spec/requests/api/graphql/project_query_spec.rb
new file mode 100644
index 00000000000..8196bcfa87c
--- /dev/null
+++ b/spec/requests/api/graphql/project_query_spec.rb
@@ -0,0 +1,39 @@
+require 'spec_helper'
+
+describe 'getting project information' do
+  include GraphqlHelpers
+
+  let(:project) { create(:project, :repository) }
+  let(:current_user) { create(:user) }
+
+  let(:query) do
+    graphql_query_for('project', 'fullPath' => project.full_path)
+  end
+
+  context 'when the user has access to the project' do
+    before do
+      project.add_developer(current_user)
+      post_graphql(query, current_user: current_user)
+    end
+
+    it 'includes the project' do
+      expect(graphql_data['project']).not_to be_nil
+    end
+
+    it_behaves_like 'a working graphql query'
+  end
+
+  context 'when the user does not have access to the project' do
+    before do
+      post_graphql(query, current_user: current_user)
+    end
+
+    it 'returns an empty field' do
+      post_graphql(query, current_user: current_user)
+
+      expect(graphql_data['project']).to be_nil
+    end
+
+    it_behaves_like 'a working graphql query'
+  end
+end
diff --git a/spec/routing/api_routing_spec.rb b/spec/routing/api_routing_spec.rb
new file mode 100644
index 00000000000..5fde4bd885b
--- /dev/null
+++ b/spec/routing/api_routing_spec.rb
@@ -0,0 +1,31 @@
+require 'spec_helper'
+
+describe 'api', 'routing' do
+  context 'when graphql is disabled' do
+    before do
+      stub_feature_flags(graphql: false)
+    end
+
+    it 'does not route to the GraphqlController' do
+      expect(get('/api/graphql')).not_to route_to('graphql#execute')
+    end
+
+    it 'does not expose graphiql' do
+      expect(get('/-/graphql-explorer')).not_to route_to('graphiql/rails/editors#show')
+    end
+  end
+
+  context 'when graphql is disabled' do
+    before do
+      stub_feature_flags(graphql: true)
+    end
+
+    it 'routes to the GraphqlController' do
+      expect(get('/api/graphql')).not_to route_to('graphql#execute')
+    end
+
+    it 'exposes graphiql' do
+      expect(get('/-/graphql-explorer')).not_to route_to('graphiql/rails/editors#show')
+    end
+  end
+end
diff --git a/spec/support/helpers/graphql_helpers.rb b/spec/support/helpers/graphql_helpers.rb
new file mode 100644
index 00000000000..30ff9a1196a
--- /dev/null
+++ b/spec/support/helpers/graphql_helpers.rb
@@ -0,0 +1,90 @@
+module GraphqlHelpers
+  # makes an underscored string look like a fieldname
+  # "merge_request" => "mergeRequest"
+  def self.fieldnamerize(underscored_field_name)
+    graphql_field_name = underscored_field_name.to_s.camelize
+    graphql_field_name[0] = graphql_field_name[0].downcase
+
+    graphql_field_name
+  end
+
+  # Run a loader's named resolver
+  def resolve(resolver_class, obj: nil, args: {}, ctx: {})
+    resolver_class.new(object: obj, context: ctx).resolve(args)
+  end
+
+  # Runs a block inside a BatchLoader::Executor wrapper
+  def batch(max_queries: nil, &blk)
+    wrapper = proc do
+      begin
+        BatchLoader::Executor.ensure_current
+        yield
+      ensure
+        BatchLoader::Executor.clear_current
+      end
+    end
+
+    if max_queries
+      result = nil
+      expect { result = wrapper.call }.not_to exceed_query_limit(max_queries)
+      result
+    else
+      wrapper.call
+    end
+  end
+
+  def graphql_query_for(name, attributes = {}, fields = nil)
+    fields ||= all_graphql_fields_for(name.classify)
+    attributes = attributes_to_graphql(attributes)
+    <<~QUERY
+    {
+      #{name}(#{attributes}) {
+        #{fields}
+      }
+    }
+    QUERY
+  end
+
+  def all_graphql_fields_for(class_name)
+    type = GitlabSchema.types[class_name.to_s]
+    return "" unless type
+
+    type.fields.map do |name, field|
+      if scalar?(field)
+        name
+      else
+        "#{name} { #{all_graphql_fields_for(field_type(field))} }"
+      end
+    end.join("\n")
+  end
+
+  def attributes_to_graphql(attributes)
+    attributes.map do |name, value|
+      "#{GraphqlHelpers.fieldnamerize(name.to_s)}: \"#{value}\""
+    end.join(", ")
+  end
+
+  def post_graphql(query, current_user: nil)
+    post api('/', current_user, version: 'graphql'), query: query
+  end
+
+  def graphql_data
+    json_response['data']
+  end
+
+  def graphql_errors
+    json_response['data']
+  end
+
+  def scalar?(field)
+    field_type(field).kind.scalar?
+  end
+
+  def field_type(field)
+    if field.type.respond_to?(:of_type)
+      field.type.of_type
+    else
+      field.type
+    end
+  end
+end
diff --git a/spec/support/matchers/graphql_matchers.rb b/spec/support/matchers/graphql_matchers.rb
new file mode 100644
index 00000000000..ba7a1c8cde0
--- /dev/null
+++ b/spec/support/matchers/graphql_matchers.rb
@@ -0,0 +1,40 @@
+RSpec::Matchers.define :require_graphql_authorizations do |*expected|
+  match do |field|
+    field_definition = field.metadata[:type_class]
+    expect(field_definition).to respond_to(:required_permissions)
+    expect(field_definition.required_permissions).to contain_exactly(*expected)
+  end
+end
+
+RSpec::Matchers.define :have_graphql_fields do |*expected|
+  match do |kls|
+    field_names = expected.map { |name| GraphqlHelpers.fieldnamerize(name) }
+    expect(kls.fields.keys).to contain_exactly(*field_names)
+  end
+end
+
+RSpec::Matchers.define :have_graphql_arguments do |*expected|
+  include GraphqlHelpers
+
+  match do |field|
+    argument_names = expected.map { |name| GraphqlHelpers.fieldnamerize(name) }
+    expect(field.arguments.keys).to contain_exactly(*argument_names)
+  end
+end
+
+RSpec::Matchers.define :have_graphql_type do |expected|
+  match do |field|
+    expect(field.type).to eq(expected.to_graphql)
+  end
+end
+
+RSpec::Matchers.define :have_graphql_resolver do |expected|
+  match do |field|
+    case expected
+    when Method
+      expect(field.metadata[:type_class].resolve_proc).to eq(expected)
+    else
+      expect(field.metadata[:type_class].resolver).to eq(expected)
+    end
+  end
+end
diff --git a/spec/support/shared_examples/requests/graphql_shared_examples.rb b/spec/support/shared_examples/requests/graphql_shared_examples.rb
new file mode 100644
index 00000000000..9b2b74593a5
--- /dev/null
+++ b/spec/support/shared_examples/requests/graphql_shared_examples.rb
@@ -0,0 +1,11 @@
+require 'spec_helper'
+
+shared_examples 'a working graphql query' do
+  include GraphqlHelpers
+
+  it 'is returns a successfull response', :aggregate_failures do
+    expect(response).to be_success
+    expect(graphql_errors['errors']).to be_nil
+    expect(json_response.keys).to include('data')
+  end
+end