Is there a "not_expects" for mocha/rspec?
I'm not a mocha expert by any means, but I suspect what you need may be supplied by a never modifier for an expectation.
RSpec 3.6 now handles this with expect(...).not_to receive(...).
From the link:
RSpec.describe "A negative message expectation" do it "passes if the message is never received" do dbl = double("Some Collaborator").as_null_object expect(dbl).not_to receive(:foo) endend