YAML Tests: Download branch when in a release branch

Author: picandocodigo

.buildkite/pipeline.yml

@@ -67,6 +67,7 @@ steps:
     env:
       RUBY_VERSION: "3.3"
       STACK_VERSION: 8.15.0-SNAPSHOT
+      ES_YAML_TESTS_BRANCH: 8.15
       TRANSPORT_VERSION: "8.3"
       RUBY_SOURCE: "ruby"
       TEST_SUITE: "platinum"

elasticsearch-api/spec/yaml-test-runner/run.rb

@@ -55,11 +55,13 @@
   CLIENT = Elasticsearch::Client.new(host: host, transport_options: transport_options)
 end
 
-
 tests_path = File.expand_path('./tmp', __dir__)
 
 logger = Logger.new($stdout)
 logger.level = Logger::WARN unless ENV['DEBUG']
 
-Elasticsearch::Tests::Downloader::run(tests_path)
+# If we're running in a release branch, download the corresponding branch for tests
+current_branch = `git rev-parse --abbrev-ref HEAD`.strip
+branch = current_branch.match(/[0-9]\.[0-9]+/)[0] || ENV['ES_YAML_TESTS_BRANCH'] || nil
+Elasticsearch::Tests::Downloader::run(tests_path, branch)
 Elasticsearch::Tests::TestRunner.new(CLIENT, tests_path, logger).run