Test-Unit 3.0 support

[rb2k]

Just noticed this:
https://rubygems.org/gems/test-unit

3.0.7 - November 14, 2014 (117 KB)
3.0.6 - November 9, 2014 (116 KB)
3.0.5 - November 8, 2014 (116 KB)
3.0.4 - November 1, 2014 (116 KB)
3.0.3 - October 28, 2014 (116 KB)
3.0.2 - October 15, 2014 (116 KB)
3.0.1 - August 5, 2014 (115 KB)
3.0.0 - August 3, 2014 (115 KB)
2.5.5 - May 18, 2013 (109 KB)

Currently, the gemspec limits to 2.5.x

Resolving dependencies...
Bundler could not find compatible versions for gem "test-unit":
  In Gemfile:
    ci_reporter_test_unit (>= 0) ruby depends on
      test-unit (~> 2.5.5) ruby

    test-unit (3.0.7)

Thought I'd file an issue :)

[shepmaster]

I don't actively use Test::Unit myself. I'd welcome any PRs from someone who'd like to get this up and running, and could probably provide some support as well.

[thevikas]

I have been using it for my rails 3 project with CI and junit xmls.
Now that Im upgradingmy project to rails 5.1, I'm not able to get xmls generated.
My current test-unit is 3.2.8.
I can try to help.