Don't provide system spec generator under Rails 5.1

Author: benoittgt

lib/generators/rspec/system/system_generator.rb

@@ -1,24 +1,25 @@
 require 'generators/rspec'
 
-module Rspec
-  module Generators
-    # @private
-    class SystemGenerator < Base
-      class_option :system_specs, :type => :boolean, :default => true,  :desc => "Generate system specs"
+if ::Rails::VERSION::STRING >= '5.1'
+  module Rspec
+    module Generators
+      # @private
+      class SystemGenerator < Base
+        class_option :system_specs, :type => :boolean, :default => true,  :desc => "Generate system specs"
 
-      def generate_system_spec
-        return unless options[:system_specs]
-        raise "System Tests are available for Rails >= 5.1" if ::Rails::VERSION::STRING < '5.1'
+        def generate_system_spec
+          return unless options[:system_specs]
 
-        template template_name, File.join('spec/system', class_path, filename)
-      end
+          template template_name, File.join('spec/system', class_path, filename)
+        end
 
-      def template_name
-        'system_spec.rb'
-      end
+        def template_name
+          'system_spec.rb'
+        end
 
-      def filename
-        "#{table_name}_spec.rb"
+        def filename
+          "#{table_name}_spec.rb"
+        end
       end
     end
   end

spec/generators/rspec/system/system_generator_spec.rb

@@ -2,19 +2,12 @@
 require 'generators/rspec/system/system_generator'
 require 'support/generators'
 
-RSpec.describe Rspec::Generators::SystemGenerator, :type => :generator do
-  setup_default_destination
+if ::Rails::VERSION::STRING >= '5.1'
+  RSpec.describe Rspec::Generators::SystemGenerator, :type => :generator do
+    setup_default_destination
 
-  describe "system specs" do
-    subject(:system_spec) { file("spec/system/posts_spec.rb") }
-    if ::Rails::VERSION::STRING < '5.1'
-      describe "are not available" do
-        it "raise error for user" do
-          expect{ run_generator(%w(posts)) }
-            .to raise_error(RuntimeError, "System Tests are available for Rails >= 5.1")
-        end
-      end
-    else
+    describe "system specs" do
+      subject(:system_spec) { file("spec/system/posts_spec.rb") }
       describe "are generated independently from the command line" do
         before do
           run_generator %w(posts)