1 files changed, 116 insertions, 0 deletions
diff --git a/qa/qa/tools/ci/qa_changes.rb b/qa/qa/tools/ci/qa_changes.rb
new file mode 100644
index 00000000000..75274961efe
--- /dev/null
+++ b/qa/qa/tools/ci/qa_changes.rb
@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+require "pathname"
+
+module QA
+  module Tools
+    module Ci
+      # Determine specific qa specs or paths to execute based on changes
+      class QaChanges
+        include Helpers
+
+        QA_PATTERN = %r{^qa/}.freeze
+        SPEC_PATTERN = %r{^qa/qa/specs/features/}.freeze
+
+        def initialize(mr_diff, mr_labels)
+          @mr_diff = mr_diff
+          @mr_labels = mr_labels
+        end
+
+        # Specific specs to run
+        #
+        # @return [String]
+        def qa_tests
+          return if mr_diff.empty?
+          # make paths relative to qa directory
+          return changed_files&.map { |path| path.delete_prefix("qa/") }&.join(" ") if only_spec_changes?
+          return qa_spec_directories_for_devops_stage&.join(" ") if non_qa_changes? && mr_labels.any?
+        end
+
+        # Qa framework changes
+        #
+        # @return [Boolean]
+        def framework_changes?
+          return false if mr_diff.empty?
+          return false if only_spec_changes?
+
+          changed_files
+            # TODO: expand pattern to other non spec paths that shouldn't trigger full suite
+            .select { |file_path| file_path.match?(QA_PATTERN) && !file_path.match?(SPEC_PATTERN) }
+            .any?
+        end
+
+        def quarantine_changes?
+          return false if mr_diff.empty?
+          return false if mr_diff.any? { |change| change[:new_file] || change[:deleted_file] }
+
+          files_count = 0
+          specs_count = 0
+          quarantine_specs_count = 0
+
+          mr_diff.each do |change|
+            path = change[:path]
+            next if File.directory?(File.expand_path("../#{path}", QA::Runtime::Path.qa_root))
+
+            files_count += 1
+            next unless path.match?(SPEC_PATTERN) && path.end_with?('_spec.rb')
+
+            specs_count += 1
+            quarantine_specs_count += 1 if change[:diff].match?(/^\+.*,? quarantine:/)
+          end
+
+          return false if specs_count == 0
+          return true if quarantine_specs_count == specs_count && quarantine_specs_count == files_count
+
+          false
+        end
+
+        private
+
+        # @return [Array]
+        attr_reader :mr_diff
+
+        # @return [Array]
+        attr_reader :mr_labels
+
+        # Are the changed files only qa specs?
+        #
+        # @return [Boolean] whether the changes files are only qa specs
+        def only_spec_changes?
+          changed_files.all? { |file_path| file_path =~ SPEC_PATTERN }
+        end
+
+        # Are the changed files only outside the qa directory?
+        #
+        # @return [Boolean] whether the changes files are outside of qa directory
+        def non_qa_changes?
+          changed_files.none? { |file_path| file_path =~ QA_PATTERN }
+        end
+
+        # Extract devops stage from MR labels
+        #
+        # @return [String] a devops stage
+        def devops_stage_from_mr_labels
+          mr_labels.find { |label| label =~ /^devops::/ }&.delete_prefix('devops::')
+        end
+
+        # Get qa spec directories for devops stage
+        #
+        # @return [Array] qa spec directories
+        def qa_spec_directories_for_devops_stage
+          devops_stage = devops_stage_from_mr_labels
+          return unless devops_stage
+
+          Dir.glob("qa/specs/**/*/").select { |dir| dir =~ %r{\d+_#{devops_stage}/$} }
+        end
+
+        # Change files in merge request
+        #
+        # @return [Array<String>]
+        def changed_files
+          @changed_files ||= mr_diff.map { |change| change[:path] } # rubocop:disable Rails/Pluck
+        end
+      end
+    end
+  end
+end