Add system/comment filter to notes api

changelogs/unreleased/notes_api_system_filter.yml

+---
+title: 25968-activity-filter-to-notes-api
+merge_request: 21159
+author: jhenkens
+type: added

lib/api/notes.rb

@@ -24,6 +24,8 @@ module API
                               desc: 'Return notes ordered by `created_at` or `updated_at` fields.'
           optional :sort, type: String, values: %w[asc desc], default: 'desc',
                           desc: 'Return notes sorted in `asc` or `desc` order.'
+          optional :activity_filter, type: String, values: UserPreference::NOTES_FILTERS.stringify_keys.keys, default: 'all_notes',
+                           desc: 'The type of notables which are returned.'
           use :pagination
         end
         # rubocop: disable CodeReuse/ActiveRecord
@@ -35,7 +37,8 @@ module API
           # at the DB query level (which we cannot in that case), the current
           # page can have less elements than :per_page even if
           # there's more than one page.
-          raw_notes = noteable.notes.with_metadata.reorder(order_options_with_tie_breaker)
+          notes_filter = UserPreference::NOTES_FILTERS[params[:activity_filter].to_sym]
+          raw_notes = noteable.notes.with_metadata.with_notes_filter(notes_filter).reorder(order_options_with_tie_breaker)
 
           # paginate() only works with a relation. This could lead to a
           # mismatch between the pagination headers info and the actual notes

spec/models/user_preference_spec.rb

@@ -5,6 +5,12 @@ require 'spec_helper'
 describe UserPreference do
   let(:user_preference) { create(:user_preference) }
 
+  describe 'notes filters global keys' do
+    it 'contains expected values' do
+      expect(UserPreference::NOTES_FILTERS.keys).to match_array([:all_notes, :only_comments, :only_activity])
+    end
+  end
+
   describe '#set_notes_filter' do
     let(:issuable) { build_stubbed(:issue) }
 

spec/requests/api/notes_spec.rb

@@ -101,6 +101,75 @@ describe API::Notes do
             expect(json_response.first['body']).to eq(cross_reference_note.note)
           end
         end
+
+        context "activity filters" do
+          let!(:user_reference_note) do
+            create :note,
+                   noteable: ext_issue, project: ext_proj,
+                   note: "Hello there general!",
+                   system: false
+          end
+
+          let(:test_url) {"/projects/#{ext_proj.id}/issues/#{ext_issue.iid}/notes"}
+
+          shared_examples 'a notes request' do
+            it 'is a note array response' do
+              expect(response).to have_gitlab_http_status(200)
+              expect(response).to include_pagination_headers
+              expect(json_response).to be_an Array
+            end
+          end
+
+          context "when not provided" do
+            let(:count) { 2 }
+
+            before do
+              get api(test_url, private_user)
+            end
+
+            it_behaves_like 'a notes request'
+
+            it 'returns all the notes' do
+              expect(json_response.count).to eq(count)
+            end
+          end
+
+          context "when all_notes provided" do
+            let(:count) { 2 }
+
+            before do
+              get api(test_url + "?activity_filter=all_notes", private_user)
+            end
+
+            it_behaves_like 'a notes request'
+
+            it 'returns all the notes' do
+              expect(json_response.count).to eq(count)
+            end
+          end
+
+          context "when provided" do
+            using RSpec::Parameterized::TableSyntax
+
+            where(:filter, :count, :system_notable) do
+              "only_comments" | 1  | false
+              "only_activity" | 1  | true
+            end
+
+            with_them do
+              before do
+                get api(test_url + "?activity_filter=#{filter}", private_user)
+              end
+
+              it_behaves_like 'a notes request'
+
+              it "properly filters the returned notables" do
+                expect(json_response.count).to eq(count)
+                expect(json_response.first["system"]).to be system_notable
+              end
+            end
+          end
+        end
       end
 
       describe "GET /projects/:id/noteable/:noteable_id/notes/:note_id" do