gistfile1.txt

# Assuming the exception is something like this
module Flicker
  class ApiError < StandardError
  end
end

def error_with_message(pattern)
  error_handling_module = Module.new
  (class << error_handling_module; self; end).instance_eval do
    define_method(:===) do |exception|
      pattern === exception.message
    end
  end
end

begin
  raise Flicker::ApiError, "thing you want to match"
rescue error_with_message(/match/)
  puts "I got ya!"
end

begin
  raise Flicker::ApiError, "This isn't going to work"
rescue error_with_message(/match/)
  puts "I got ya!"
end