Raise error if using Sidekiq 7+ and be_delayed

lib/rspec/sidekiq/configuration.rb

@@ -1,13 +1,22 @@
+require "rubygems"
+
 module RSpec
   module Sidekiq
     class Configuration
-      attr_accessor :clear_all_enqueued_jobs, :enable_terminal_colours, :warn_when_jobs_not_processed_by_sidekiq
+      attr_accessor :clear_all_enqueued_jobs,
+        :enable_terminal_colours,
+        :warn_when_jobs_not_processed_by_sidekiq
 
       def initialize
         @clear_all_enqueued_jobs = true
         @enable_terminal_colours = true
+
         @warn_when_jobs_not_processed_by_sidekiq = true
       end
+
+      def sidekiq_gte_7?
+        Gem::Version.new(::Sidekiq::VERSION) >= "7"
+      end
     end
   end
 end

lib/rspec/sidekiq/matchers/be_delayed.rb

@@ -7,6 +7,10 @@ def be_delayed(*expected_arguments)
 
       class BeDelayed
         def initialize(*expected_arguments)
+          raise <<~MSG if RSpec::Sidekiq.configuration.sidekiq_gte_7?
+            Use of the be_delayed matcher with Sidekiq 7+ is not possible. Try refactoring to a Sidekiq Job with `perform_at` or `perform_in` and the `have_enqueued_sidekiq_job` matcher
+          MSG
+
           @expected_arguments = expected_arguments
         end
 

spec/rspec/sidekiq/matchers/be_delayed_spec.rb

@@ -1,8 +1,10 @@
-require 'spec_helper'
+require "spec_helper"
 
 RSpec.describe RSpec::Sidekiq::Matchers::BeDelayed do
   if RSpec.configuration.sidekiq_gte_7
-    skip("Be Delayed is only valid for Sidekiq <7")
+    it "should raise an error" do
+      expect { described_class.new }.to raise_error(/Use of the be_delayed matcher with Sidekiq 7\+ is not possible/)
+    end
   else
     let(:delay_subject) { RSpec::Sidekiq::Matchers::BeDelayed.new }
     let(:delay_with_arguments_subject) { RSpec::Sidekiq::Matchers::BeDelayed.new Object }