Add admin users serializer and entity

- Created new serializer and entity to generate data for the admin
users table
- Added new tests
- Added changelog

app/helpers/admin/user_actions_helper.rb

+# frozen_string_literal: true
+
+module Admin
+  module UserActionsHelper
+    def admin_actions(user)
+      return [] if user.internal?
+
+      @actions ||= ['edit']
+
+      return @actions if user == current_user
+
+      @user ||= user
+
+      blocked_actions
+      deactivate_actions
+      unlock_actions
+      delete_actions
+
+      @actions
+    end
+
+    private
+
+    def blocked_actions
+      if @user.ldap_blocked?
+        @actions << 'ldap'
+      elsif @user.blocked? && @user.blocked_pending_approval?
+        @actions << 'approve'
+        @actions << 'reject'
+      elsif @user.blocked?
+        @actions << 'unblock'
+      else
+        @actions << 'block'
+      end
+    end
+
+    def deactivate_actions
+      if @user.can_be_deactivated?
+        @actions << 'deactivate'
+      elsif @user.deactivated?
+        @actions << 'activate'
+      end
+    end
+
+    def unlock_actions
+      @actions << 'unlock' if @user.access_locked?
+    end
+
+    def delete_actions
+      return unless can?(current_user, :destroy_user, @user) && !@user.blocked_pending_approval? && @user.can_be_removed?
+
+      @actions << 'delete'
+      @actions << 'delete_with_contributions'
+    end
+  end
+end

app/serializers/admin/user_entity.rb

+# frozen_string_literal: true
+
+module Admin
+  class UserEntity < API::Entities::UserSafe
+    include RequestAwareEntity
+    include UsersHelper
+    include UserActionsHelper
+
+    expose :created_at
+    expose :email
+    expose :last_activity_on
+    expose :avatar_url
+    expose :badges do |user|
+      user_badges_in_admin_section(user)
+    end
+
+    expose :projects_count do |user|
+      user.authorized_projects.length
+    end
+
+    expose :actions do |user|
+      admin_actions(user)
+    end
+
+    private
+
+    def current_user
+      options[:current_user]
+    end
+  end
+end

app/serializers/admin/user_serializer.rb

+# frozen_string_literal: true
+
+module Admin
+  class UserSerializer < BaseSerializer
+    entity UserEntity
+  end
+end

changelogs/unreleased/285103-serialize-admin-users.yml

+---
+title: Add admin users serializer and entity
+merge_request: 48791
+author:
+type: added

spec/helpers/admin/user_actions_helper_spec.rb

+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe Admin::UserActionsHelper do
+  describe '#admin_actions' do
+    let_it_be(:current_user) { build(:user) }
+
+    subject { helper.admin_actions(user) }
+
+    before do
+      allow(helper).to receive(:current_user).and_return(current_user)
+      allow(helper).to receive(:can?).with(current_user, :destroy_user, user).and_return(true)
+    end
+
+    context 'the user is a bot' do
+      let_it_be(:user) { build(:user, :bot) }
+
+      it { is_expected.to be_empty }
+    end
+
+    context 'the current user and user are the same' do
+      let_it_be(:user) { build(:user) }
+      let_it_be(:current_user) { user }
+
+      it { is_expected.to contain_exactly("edit") }
+    end
+
+    context 'the user is a standard user' do
+      let_it_be(:user) { create(:user) }
+
+      it { is_expected.to contain_exactly("edit", "block", "deactivate", "delete", "delete_with_contributions") }
+    end
+
+    context 'the user is an admin user' do
+      let_it_be(:user) { create(:user, :admin) }
+
+      it { is_expected.to contain_exactly("edit", "block", "deactivate", "delete", "delete_with_contributions") }
+    end
+
+    context 'the user is blocked by LDAP' do
+      let_it_be(:user) { create(:omniauth_user, :ldap_blocked) }
+
+      it { is_expected.to contain_exactly("edit", "ldap", "delete", "delete_with_contributions") }
+    end
+
+    context 'the user is blocked pending approval' do
+      let_it_be(:user) { create(:user, :blocked_pending_approval) }
+
+      it { is_expected.to contain_exactly("edit", "approve", "reject") }
+    end
+
+    context 'the user is blocked' do
+      let_it_be(:user) { create(:user, :blocked) }
+
+      it { is_expected.to contain_exactly("edit", "unblock", "delete", "delete_with_contributions") }
+    end
+
+    context 'the user is deactivated' do
+      let_it_be(:user) { create(:user, :deactivated) }
+
+      it { is_expected.to contain_exactly("edit", "block", "activate", "delete", "delete_with_contributions") }
+    end
+
+    context 'the user is locked' do
+      let_it_be(:user) { create(:user) }
+
+      before do
+        user.lock_access!
+      end
+
+      it {
+        is_expected.to contain_exactly(
+          "edit",
+          "block",
+          "deactivate",
+          "unlock",
+          "delete",
+          "delete_with_contributions"
+        )
+      }
+    end
+
+    context 'the current_user does not have permission to delete the user' do
+      let_it_be(:user) { build(:user) }
+
+      before do
+        allow(helper).to receive(:can?).with(current_user, :destroy_user, user).and_return(false)
+      end
+
+      it { is_expected.to contain_exactly("edit", "block", "deactivate") }
+    end
+
+    context 'the user is a sole owner of a group' do
+      let_it_be(:group) { create(:group) }
+      let_it_be(:user) { create(:user) }
+
+      before do
+        group.add_owner(user)
+      end
+
+      it { is_expected.to contain_exactly("edit", "block", "deactivate") }
+    end
+  end
+end

spec/serializers/admin/user_entity_spec.rb

+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe Admin::UserEntity do
+  let_it_be(:user) { build_stubbed(:user) }
+  let(:request) { double('request') }
+
+  let(:entity) do
+    described_class.new(user, request: request)
+  end
+
+  describe '#as_json' do
+    subject { entity.as_json&.keys }
+
+    it 'exposes correct attributes' do
+      is_expected.to contain_exactly(
+        :id,
+        :name,
+        :created_at,
+        :email,
+        :username,
+        :last_activity_on,
+        :avatar_url,
+        :badges,
+        :projects_count,
+        :actions
+      )
+    end
+  end
+end

spec/serializers/admin/user_serializer_spec.rb

+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe Admin::UserSerializer do
+  let(:resource) { build(:user) }
+
+  subject { described_class.new.represent(resource).keys }
+
+  context 'when there is a single object provided' do
+    it 'contains important elements for the admin user table' do
+      is_expected.to contain_exactly(
+        :id,
+        :name,
+        :created_at,
+        :email,
+        :username,
+        :last_activity_on,
+        :avatar_url,
+        :badges,
+        :projects_count,
+        :actions
+      )
+    end
+  end
+end