Adding an Observer to Test::Unit::TestResult

[cgmjr]

Can anyone share with me on how you would subscribe
to Test::Unit::TestResult with a Observer? Currently I have working
this, but it seems clumsy to me:
require 'test/unit'
require 'enumerator'

class Report_failure

def initialize
tresultinstance=ObjectSpace.enum_for( :each_object,
Test::Unit::TestResult ).to_a
tresultinstance[0].add_listener(Test::Unit::TestResult::FAULT,
&methodnotify_failure))
end

def notify_failure(failure)
printf "Observed failure =%s \n", failure.long_display
end
end

But in Ed. 1 of Dave, Chad, and Andy's book there's the cool
add_observer bit, as in:

....
def initialize(ticker, limit)
@limit = limit
ticker.add_observer(self) # all warners are observers
end
....

I need some style hints. Has add_observer been deprecated in 1.8.2?

Many thanks!
g.