Windows builds were recently introduced to the Logstash Jenkins builds, and have not fully worked.

For example: https://logstash-ci.elastic.co/job/elastic+logstash+master+multijob-windows-compatibility/

Below is the list to get Windows builds fully functional:

• Fix the Java core tests Fix gradle tests on Windows #7716
• Fix Ingest Conversion tool tests Ingest Conversion Tool Tests Fail on Windows #7642
• Fix Jenkins $HOME to ensure proper escaping. https://github.com/elastic/infra/pull/2483
• Allow long file names on Jenkins. https://github.com/elastic/infra/issues/2487
  (Jenkins Windows Build's show a false positive success.  #7634 (comment))
• Fix Null Pointer from dsl.instance_eval issue. See this comment, and Plugin manager (during dev bootstrap) is crashing with NullPointerException #7768
• [6.0, master] Fix Ruby test failures Windows build fixes #8116 Windows core specs failures #8074
• [5.6] Fix Ruby test failures Windows build fixes for 5.6 #8125
• [5.5] Fix build & tests 5.5 backport of windows build/test fixes #8354
• fix logstash.bat, setup.bat and rspec.bat have bin/setup.bat apply the same logic as bin/logstash.lib.sh #8126 windows launch scripts #8178 pick jvm.options for rspec.bat #8359
• Evaluate if builds need to be run on Windows 2012. See this comment and the conversation below.
• Fix false positive success from ci\unit_tests.bat See this comment and this comment
• Support builds on Windows 2016 w/ longfile name fix.
• Support builds on Windows 2012 (no long file name fix available) dynamically assign drive letter to WORKSPACE env var #8398
• Discuss updating the support matrix for Windows to include a footnote about the long file names and potential workarounds. (see below - logged follow up Windows installation instructions #8424)

My notes to run locally:

ensure that JRuby is installed at C:
For example: C:\jruby-9.1.12.0
Need to run from cmd, not powershell, but can launch cmd from powershell for a better cmd.
From powershell:
clone the repo

cmd
set JRUBYSRCDIR=C:\
ci\ci_test.bat