Implement CI/CD bridge configuration entry

ee/lib/ee/gitlab/ci/config/entry/bridge.rb

+# frozen_string_literal: true
+
+module EE
+  module Gitlab
+    module Ci
+      module Config
+        module Entry
+          ##
+          # Entry that represents a CI/CD Bridge job that is responsible for
+          # defining a downstream project trigger.
+          #
+          class Bridge < ::Gitlab::Config::Entry::Node
+            include ::Gitlab::Config::Entry::Configurable
+            include ::Gitlab::Config::Entry::Attributable
+
+            ALLOWED_KEYS = %i[trigger].freeze
+
+            validations do
+              validates :config, allowed_keys: ALLOWED_KEYS
+              validates :config, presence: true
+              validates :trigger, presence: true
+              validates :name, presence: true
+              validates :name, type: Symbol
+            end
+
+            entry :trigger, ::EE::Gitlab::Ci::Config::Entry::Trigger,
+              description: 'CI/CD Bridge downstream trigger definition.'
+
+            helpers :trigger
+            attributes ALLOWED_KEYS
+
+            def name
+              @metadata[:name]
+            end
+
+            def value
+              { name: name, trigger: trigger_value }
+            end
+          end
+        end
+      end
+    end
+  end
+end

ee/spec/lib/ee/gitlab/ci/config/entry/bridge_spec.rb

+require 'fast_spec_helper'
+require_dependency 'active_model'
+
+describe EE::Gitlab::Ci::Config::Entry::Bridge do
+  subject { described_class.new(config, name: :my_trigger) }
+
+  before do
+    subject.compose!
+  end
+
+  context 'when trigger config is a non-empty string' do
+    let(:config) { { trigger: 'some/project' } }
+
+    describe '#valid?' do
+      it { is_expected.to be_valid }
+    end
+
+    describe '#value' do
+      it 'is returns a bridge job configuration' do
+        expect(subject.value).to eq(name: :my_trigger,
+                                    trigger: { project: 'some/project' })
+      end
+    end
+  end
+
+  context 'when bridge trigger is a hash' do
+    let(:config) do
+      { trigger: { project: 'some/project', branch: 'feature' } }
+    end
+
+    describe '#valid?' do
+      it { is_expected.to be_valid }
+    end
+
+    describe '#value' do
+      it 'is returns a bridge job configuration hash' do
+        expect(subject.value).to eq(name: :my_trigger,
+                                    trigger: { project: 'some/project',
+                                               branch: 'feature' })
+      end
+    end
+  end
+
+  context 'when trigger config is nil' do
+    let(:config) { { trigger: nil } }
+
+    describe '#valid?' do
+      it { is_expected.not_to be_valid }
+    end
+
+    describe '#errors' do
+      it 'is returns an error about empty trigger config' do
+        expect(subject.errors.first).to match /can't be blank/
+      end
+    end
+  end
+
+  context 'when bridge config contains unknown keys' do
+    let(:config) { { unknown: 123 } }
+
+    describe '#valid?' do
+      it { is_expected.not_to be_valid }
+    end
+
+    describe '#errors' do
+      it 'is returns an error about unknown config key' do
+        expect(subject.errors.first)
+          .to match /config contains unknown keys: unknown/
+      end
+    end
+  end
+
+  context 'when bridge configuration is not valid' do
+    let(:config) { { script: 'something' } }
+
+    describe '#valid?' do
+      it { is_expected.not_to be_valid }
+    end
+
+    describe '#errors' do
+      it 'returns an error message' do
+        expect(subject.errors.first)
+          .to match /contains unknown keys: script/
+      end
+    end
+  end
+end