1 files changed, 61 insertions, 0 deletions
diff --git a/tooling/lib/tooling/mappings/js_to_system_specs_mappings.rb b/tooling/lib/tooling/mappings/js_to_system_specs_mappings.rb
new file mode 100644
index 00000000000..365e466011b
--- /dev/null
+++ b/tooling/lib/tooling/mappings/js_to_system_specs_mappings.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require 'active_support/inflector'
+
+require_relative 'base'
+require_relative '../../../../lib/gitlab_edition'
+
+# Returns system specs files that are related to the JS files that were changed in the MR.
+module Tooling
+  module Mappings
+    class JsToSystemSpecsMappings < Base
+      def initialize(js_base_folder: 'app/assets/javascripts', system_specs_base_folder: 'spec/features')
+        @js_base_folder           = js_base_folder
+        @js_base_folders          = folders_for_available_editions(js_base_folder)
+        @system_specs_base_folder = system_specs_base_folder
+
+        # Cannot be extracted to a constant, as it depends on a variable
+        @first_js_folder_extract_regexp = %r{
+          (?:.*/)?             # Skips the GitLab edition (e.g. ee/, jh/)
+          #{@js_base_folder}/  # Most likely app/assets/javascripts/
+          ([\w-]*)             # Captures the first folder
+        }x
+      end
+
+      def execute(changed_files)
+        filter_files(changed_files).flat_map do |edition, js_files|
+          js_keywords_regexp = Regexp.union(construct_js_keywords(js_files))
+
+          system_specs_for_edition(edition).select do |system_spec_file|
+            system_spec_file if js_keywords_regexp.match?(system_spec_file)
+          end
+        end
+      end
+
+      # Keep the files that are in the @js_base_folders folders
+      #
+      # Returns a hash, where the key is the GitLab edition, and the values the JS specs
+      def filter_files(changed_files)
+        selected_files = changed_files.select do |filename|
+          filename.start_with?(*@js_base_folders) && File.exist?(filename)
+        end
+
+        selected_files.group_by { |filename| filename[/^#{Regexp.union(::GitlabEdition.extensions)}/] }
+      end
+
+      # Extract keywords in the JS filenames to be used for searching matching system specs
+      def construct_js_keywords(js_files)
+        js_files.map do |js_file|
+          filename = js_file.scan(@first_js_folder_extract_regexp).flatten.first
+          filename.singularize
+        end.uniq
+      end
+
+      def system_specs_for_edition(edition)
+        all_files_in_folders_glob = File.join(@system_specs_base_folder, '**', '*')
+        all_files_in_folders_glob = File.join(edition, all_files_in_folders_glob) if edition
+        Dir[all_files_in_folders_glob].select { |f| File.file?(f) }
+      end
+    end
+  end
+end