Add RSpec 4 compatibility (#17652)

* Remove outdated option

04078317ba

* Use the non-globally exposed RSpec syntax

https://github.com/rspec/rspec-core/pull/2803

* Use the non-globally exposed RSpec syntax, cont

https://github.com/rspec/rspec-core/pull/2803

* Comply to strict predicate matchers

See:
 - https://github.com/rspec/rspec-expectations/pull/1195
 - https://github.com/rspec/rspec-expectations/pull/1196
 - https://github.com/rspec/rspec-expectations/pull/1277

plugins/discourse-narrative-bot/spec/discourse_narrative_bot/new_user_narrative_spec.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-describe DiscourseNarrativeBot::NewUserNarrative do
+RSpec.describe DiscourseNarrativeBot::NewUserNarrative do
   fab!(:welcome_topic) { Fabricate(:topic, title: 'Welcome to Discourse') }
   fab!(:narrative_bot) { ::DiscourseNarrativeBot::Base.new }
   fab!(:discobot_user) { narrative_bot.discobot_user }

plugins/discourse-narrative-bot/spec/discourse_narrative_bot/store_spec.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-describe DiscourseNarrativeBot::Store do
+RSpec.describe DiscourseNarrativeBot::Store do
   describe '.set' do
     it 'should set the right value in the plugin store' do
       key = 'somekey'

plugins/discourse-narrative-bot/spec/discourse_narrative_bot/track_selector_spec.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-describe DiscourseNarrativeBot::TrackSelector do
+RSpec.describe DiscourseNarrativeBot::TrackSelector do
   let(:user) { Fabricate(:user) }
   let(:narrative_bot) { ::DiscourseNarrativeBot::Base.new }
   let(:discobot_user) { narrative_bot.discobot_user }

plugins/discourse-narrative-bot/spec/jobs/onceoff/remap_old_bot_images_spec.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-describe Jobs::DiscourseNarrativeBot::RemapOldBotImages do
+RSpec.describe Jobs::DiscourseNarrativeBot::RemapOldBotImages do
   context "when bot's post contains an old link" do
     let!(:post) do
       Fabricate(:post,

plugins/discourse-narrative-bot/spec/requests/discobot_certificate_spec.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-describe "Discobot Certificate" do
+RSpec.describe "Discobot Certificate" do
   let(:user) { Fabricate(:user, name: 'Jeff Atwood') }
 
   let(:params) {

plugins/discourse-narrative-bot/spec/requests/discobot_welcome_post_spec.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-describe "Discobot welcome post" do
+RSpec.describe "Discobot welcome post" do
   let(:user) { Fabricate(:user) }
 
   before do

plugins/discourse-narrative-bot/spec/user_spec.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-describe User do
+RSpec.describe User do
   let(:user) { Fabricate(:user) }
   let(:profile_page_url) { "#{Discourse.base_url}/users/#{user.username}" }