Make it possible to combine extended CI/CD statuses

This commit also makes it possible to configure exclusive groups.
There can be only one detailed status matched within an exclusive group,
which is important from the performance perspective.

lib/gitlab/ci/status/factory.rb

@@ -8,10 +8,12 @@ module Gitlab
         end
 
         def fabricate!
-          if extended_status
-            extended_status.new(core_status)
-          else
+          if extended_statuses.none?
             core_status
+          else
+            extended_statuses.inject(core_status) do |status, extended|
+              extended.new(status)
+            end
           end
         end
 
@@ -36,10 +38,14 @@ module Gitlab
             .extend(self.class.common_helpers)
         end
 
-        def extended_status
-          @extended ||= self.class.extended_statuses.find do |status|
-            status.matches?(@subject, @user)
+        def extended_statuses
+          return @extended_statuses if defined?(@extended_statuses)
+
+          groups = self.class.extended_statuses.map do |group|
+            Array(group).find { |status| status.matches?(@subject, @user) }
           end
+
+          @extended_statuses = groups.flatten.compact
         end
       end
     end

spec/lib/gitlab/ci/status/factory_spec.rb

 require 'spec_helper'
 
 describe Gitlab::Ci::Status::Factory do
-  subject do
-    described_class.new(resource, user)
-  end
-
   let(:user) { create(:user) }
-
-  let(:status) { subject.fabricate! }
+  let(:status) { factory.fabricate! }
+  let(:factory) { described_class.new(resource, user) }
 
   context 'when object has a core status' do
     HasStatus::AVAILABLE_STATUSES.each do |core_status|
       context "when core status is #{core_status}" do
-        let(:resource) { double(status: core_status) }
+        let(:resource) { double('resource', status: core_status) }
 
         it "fabricates a core status #{core_status}" do
           expect(status).to be_a(
@@ -21,4 +17,91 @@ describe Gitlab::Ci::Status::Factory do
       end
     end
   end
+
+  context 'when resource supports multiple extended statuses' do
+    let(:resource) { double('resource', status: :success) }
+
+    let(:first_extended_status) do
+      Class.new(SimpleDelegator) do
+        def first_method
+          'first return value'
+        end
+
+        def second_method
+          'second return value'
+        end
+
+        def self.matches?(*)
+          true
+        end
+      end
+    end
+
+    let(:second_extended_status) do
+      Class.new(SimpleDelegator) do
+        def first_method
+          'decorated return value'
+        end
+
+        def third_method
+          'third return value'
+        end
+
+        def self.matches?(*)
+          true
+        end
+      end
+    end
+
+    shared_examples 'compound decorator factory' do
+      it 'fabricates compound decorator' do
+        expect(status.first_method).to eq 'decorated return value'
+        expect(status.second_method).to eq 'second return value'
+        expect(status.third_method).to eq 'third return value'
+      end
+
+      it 'delegates to core status' do
+        expect(status.text).to eq 'passed'
+      end
+
+      it 'latest matches status becomes a status name' do
+        expect(status.class).to eq second_extended_status
+      end
+    end
+
+    context 'when exclusive statuses are matches' do
+      before do
+        allow(described_class).to receive(:extended_statuses)
+          .and_return([[first_extended_status, second_extended_status]])
+      end
+
+      it 'fabricates compound decorator' do
+        expect(status.first_method).to eq 'first return value'
+        expect(status.second_method).to eq 'second return value'
+        expect(status).not_to respond_to(:third_method)
+      end
+
+      it 'delegates to core status' do
+        expect(status.text).to eq 'passed'
+      end
+    end
+
+    context 'when exclusive statuses are not matched' do
+      before do
+        allow(described_class).to receive(:extended_statuses)
+          .and_return([[first_extended_status], [second_extended_status]])
+      end
+
+      it_behaves_like 'compound decorator factory'
+    end
+
+    context 'when using simplified status grouping' do
+      before do
+        allow(described_class).to receive(:extended_statuses)
+          .and_return([first_extended_status, second_extended_status])
+      end
+
+      it_behaves_like 'compound decorator factory'
+    end
+  end
 end