Added package_type to group packages api

Added package_type param to api options
Updated tests
Updated documentation
Added changelog entry

changelogs/unreleased/197918-add-package-type-param-to-group-packages-api.yml

+---
+title: Add package_type as a filter option to the group packages list API endpoint
+merge_request: 26833
+author:
+type: added

doc/api/packages.md

@@ -67,6 +67,7 @@ GET /groups/:id/packages
 | `exclude_subgroups` | boolean | false | If the param is included as true, packages from projects from subgroups are not listed. Default is `false`. |
 | `order_by`| string | no | The field to use as order. One of `created_at` (default), `name`, `version`, `type`, or `project_path`. |
 | `sort`    | string | no | The direction of the order, either `asc` (default) for ascending order or `desc` for descending order. |
+| `package_type` | string | no | Filter the returned packages by type. One of `conan`, `maven`, `npm` or `nuget`. (_Introduced in GitLab 12.9_) |
 
 ```shell
 curl --header "PRIVATE-TOKEN: <your_access_token>" https://gitlab.example.com/api/v4/groups/:id/packages?exclude_subgroups=true

ee/lib/api/group_packages.rb

@@ -25,14 +25,14 @@ module API
                             desc: 'Return packages ordered by `created_at`, `name`, `version` or `type` fields.'
         optional :sort, type: String, values: %w[asc desc], default: 'asc',
                         desc: 'Return packages sorted in `asc` or `desc` order.'
+        optional :package_type, type: String, values: Packages::Package.package_types.keys,
+                                desc: 'Return packages of a certain type'
       end
       get ':id/packages' do
         packages = Packages::GroupPackagesFinder.new(
           current_user,
           user_group,
-          exclude_subgroups: params[:exclude_subgroups],
-          order_by: params[:order_by],
-          sort: params[:sort]
+          declared(params).slice(:exclude_subgroups, :order_by, :sort, :package_type)
         ).execute
 
         present paginate(packages), with: EE::API::Entities::Package, user: current_user, group: true

ee/spec/requests/api/group_packages_spec.rb

@@ -3,8 +3,8 @@
 require 'spec_helper'
 
 describe API::GroupPackages do
-  let(:group) { create(:group, :public) }
-  let(:project) { create(:project, :public, namespace: group, name: 'project A') }
+  let_it_be(:group) { create(:group, :public) }
+  let_it_be(:project) { create(:project, :public, namespace: group, name: 'project A') }
   let!(:package1) { create(:npm_package, project: project, version: '3.1.0', name: "@#{project.root_namespace.path}/foo1") }
   let!(:package2) { create(:nuget_package, project: project, version: '2.0.4') }
   let(:user) { create(:user) }
@@ -128,6 +128,31 @@ describe API::GroupPackages do
 
         it_behaves_like 'returns paginated packages'
       end
+
+      context 'filtering on package_type' do
+        let_it_be(:package1) { create(:conan_package, project: project) }
+        let_it_be(:package2) { create(:maven_package, project: project) }
+        let_it_be(:package3) { create(:npm_package, project: project) }
+        let_it_be(:package4) { create(:nuget_package, project: project) }
+
+        context 'for each type' do
+          %w[conan maven npm nuget].each do |package_type|
+            it "returns #{package_type} packages" do
+              url = "/groups/#{group.id}/packages?package_type=#{package_type}"
+
+              get api(url)
+
+              expect(json_response.map { |package| package['package_type'] }).to eq([package_type])
+            end
+          end
+        end
+
+        context 'does not accept non supported package_type value' do
+          let(:url) { "/groups/#{group.id}/packages?package_type=foo" }
+
+          it_behaves_like 'returning response status', :bad_request
+        end
+      end
     end
 
     context 'with packages feature disabled' do