Cool way to provide a long multi-line description for an Exception

LongExceptionDescription.rb

# taken from rspec-core's file pending.rb

if block_given?
  raise ArgumentError, <<-EOS.gsub(/^\s+\|/, '')
    |The semantics of `RSpec::Core::Pending#pending` have changed in
    |RSpec 3. In RSpec 2.x, it caused the example to be skipped. In
    |RSpec 3, the rest of the example is still run but is expected to
    |fail, and will be marked as a failure (rather than as pending) if
    |the example passes.
    |
    |Passing a block within an example is now deprecated. Marking the
    |example as pending provides the same behavior in RSpec 3 which was
    |provided only by the block in RSpec 2.x.
    |
    |Move the code in the block provided to `pending` into the rest of
    |the example body.
    |
    |Called from #{CallerFilter.first_non_rspec_line}.
    |
  EOS
end