Why is Rubinius running this method?

Shell output

$ rvm use default
Using /Users/james/.rvm/gems/ree-1.8.7-2010.02
$ ruby testcase_issue.rb 
Loaded suite testcase_issue
Started
.
Finished in 0.000416 seconds.

1 tests, 0 assertions, 0 failures, 0 errors


$ rvm use 1.9.2
Using /Users/james/.rvm/gems/ruby-1.9.2-p180
$ ruby testcase_issue.rb
Loaded suite testcase_issue
Started
.
Finished in 0.000437 seconds.

1 tests, 0 assertions, 0 failures, 0 errors, 0 skips

Test run options: --seed 46451


$ rvm use rbx
Using /Users/james/.rvm/gems/rbx-head
$ ruby testcase_issue.rb
Loaded suite testcase_issue
Started
.E
Finished in 0.001179 seconds.

  1) Error:
test_thing(Blah):
RuntimeError: Why am I being called!
    testcase_issue.rb:14:in `test_thing'
    kernel/bootstrap/array.rb:76:in `each'
    kernel/bootstrap/array.rb:76:in `each'

2 tests, 0 assertions, 0 failures, 1 errors

testcase_issue.rb

require "test/unit"

class Blah < Test::Unit::TestCase
  def test_something
  end
end

def test_other_thing(*args, &block)
  raise "I should not be called because I am not in a TestCase, and am not."
end

1.times do
  def test_thing(*args, &block)
    raise "Why am I being called!"
  end
end