RSpec stop method

RSpec stop method

Quick rspec question here.
Given the following test...
it 'sets the correct params' do
property = 'blahblah'
expect(ConnectionClass).to receive(:new).with({ opt1: param1, opt2:
property })
subject.send(:do_things, nil, nil).and_return_nil
end
and the following method...
private
def do_things(param1, param2)
connection = ConnectionClass.new(opt1: param1, opt2: param2)
##
# How do i stop the test from continue beyond this point? :(
##
some_var = connection.build_request do |blah|
# ...
end
some_var.some_attribute
end
Running the test results in the following failure:
Failures:
1) Klass#do_things sets the correct params
Failure/Error: subject.send(:do_things, nil, nil).and_return_nil
NoMethodError:
undefined method `build_request' for nil:NilClass
# ./lib/blah/Klass.rb:46:in `make_request'
# ./spec/lib/blah/Klass_spec.rb:79:in `block (3 levels) in <top
(required)>'
For this test, all i care about is that ConnectionClass is initialized
correctly -- how can i prevent the call to build_request and eventual
some_attribute?
Thank you