Fix method name truncation for multibyte strings (redux)

Changelog.md

@@ -1,6 +1,11 @@
 ### Development
 [Full Changelog](https://github.com/rspec/rspec-rails/compare/v5.0.0...main)
 
+Bug Fixes:
+
+* Limit multibyte example descriptions when used in system tests for #method_name
+  which ends up as screenshot names etc. (@y-yagi, #2405, #2487)
+
 ### 5.0.0 / 2021-03-09
 [Full Changelog](https://github.com/rspec/rspec-rails/compare/v4.1.1...v5.0.0)
 

lib/rspec/rails/example/system_example_group.rb

@@ -41,7 +41,7 @@ def method_name
         @method_name ||= [
           self.class.name.underscore,
           RSpec.current_example.description.underscore
-        ].join("_").tr(CHARS_TO_TRANSLATE.join, "_")[0...200] + "_#{rand(1000)}"
+        ].join("_").tr(CHARS_TO_TRANSLATE.join, "_").byteslice(0...200).scrub("") + "_#{rand(1000)}"
       end
 
       # Delegates to `Rails.application`.

spec/rspec/rails/example/system_example_group_spec.rb

@@ -15,6 +15,18 @@ module RSpec::Rails
           expect(example.send(:method_name)).to start_with('method_name')
         end
       end
+
+      it "handles long method names which include unicode characters" do
+        group =
+          RSpec::Core::ExampleGroup.describe do
+            include SystemExampleGroup
+          end
+
+        example = group.new
+        allow(example.class).to receive(:name) { "really long unicode example name - #{'あ'*100}" }
+
+        expect(example.send(:method_name).bytesize).to be <= 210
+      end
     end
 
     describe '#driver' do