Add dependent destroy and related test for deleting a user

app/controllers/admin/users_controller.rb

@@ -33,6 +33,7 @@ module Admin
 
     def destroy
       @user = User.find(params[:id])
+      @user.events.destroy_all
       @user.destroy
       redirect_to admin_users_path, notice: 'User got deleted'
     end

app/models/user.rb

@@ -16,7 +16,7 @@ class User < ActiveRecord::Base
                   :name, :email_public, :biography, :nickname, :affiliation
 
   has_many :event_users, dependent: :destroy
-  has_many :events, -> { uniq }, through: :event_users
+  has_many :events, -> { uniq }, through: :event_users, dependent: :destroy
   has_many :registrations, dependent: :destroy
   has_many :votes, dependent: :destroy
   has_many :voted_events, through: :votes, source: :events

spec/models/user_spec.rb

@@ -26,6 +26,11 @@ describe User do
     expect(user_with_all_roles.roles[2]).to eq(admin_role)
   end
 
+  it { should have_many(:events).dependent(:destroy) }
+  it { should have_many(:event_users).dependent(:destroy) }
+  it { should have_many(:registrations).dependent(:destroy) }
+  it { should have_many(:votes).dependent(:destroy) }
+
   describe '#role?' do
     shared_examples '#role?' do |user, role, expected|
       it "returns #{expected} for #{role}" do