[CI] Log test results to a file in Buildkite

Author: picandocodigo

.buildkite/pipeline.yml

@@ -33,6 +33,7 @@ steps:
       TRANSPORT_VERSION: "{{ matrix.transport }}"
       RUBY_SOURCE: "{{ matrix.ruby_source }}"
       TEST_SUITE: "platinum"
+      DEBUG: true
     command: ./.buildkite/run-yaml-tests.sh
   - wait: ~
     continue_on_failure: true

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

@@ -56,8 +56,8 @@
          end
 
 tests_path = File.expand_path('./tmp', __dir__)
-
-logger = Logger.new($stdout)
+logfile = File.expand_path "../../tmp/tests-for-transport-#{ENV['TRANSPORT_VERSION']}-ruby-#{ENV['RUBY_VERSION']}.log", __dir__
+logger = Logger.new(File.open(logfile, 'w'))
 logger.level = Logger::WARN unless ENV['DEBUG']
 
 # If we're running in a release branch, download the corresponding branch for tests