Fix puma loading in Rails 5.1 (#1884)

* Fix puma loading in Rails 5.1

* Prevent system tests loading without capybara

* Allow rescuing exceptions for system test

* Fix rubocop lints

Author: Sam Phippen

lib/rspec/rails/configuration.rb

@@ -51,7 +51,14 @@ def self.add_test_type_configurations(config)
       config.include RSpec::Rails::Matchers
 
       if ActionPack::VERSION::STRING >= "5.1"
-        config.include RSpec::Rails::SystemExampleGroup, :type => :system
+        begin
+          require 'puma'
+          require 'capybara'
+          config.include RSpec::Rails::SystemExampleGroup, :type => :system
+        # rubocop:disable Lint/HandleExceptions
+        rescue LoadError
+          # rubocop:enable Lint/HandleExceptions
+        end
       end
     end
 

lib/rspec/rails/example.rb

@@ -9,5 +9,12 @@
 require 'rspec/rails/example/job_example_group'
 require 'rspec/rails/example/feature_example_group'
 if ActionPack::VERSION::STRING >= "5.1"
-  require 'rspec/rails/example/system_example_group'
+  begin
+    require 'puma'
+    require 'capybara'
+    require 'rspec/rails/example/system_example_group'
+  # rubocop:disable Lint/HandleExceptions
+  rescue LoadError
+    # rubocop:enable Lint/HandleExceptions
+  end
 end