Some stubs in Rspec 2.9 doesn't work as expected

[rnaveiras]

It seems some tests are broken in rspec 2.9 because stub doesn't behave as expected when receives a block

For instance:

app.stub(:subscribe) do |_, _, handler|
  handler.call(:data => 'hey')
end

In rspec 2.9 always fires

NoMethodError:
  undefined method `call' for nil:NilClass