RSpec: how to test if a method was called?

Question

When writing RSpec tests, I find myself writing a lot of code that looks like this in order to ensure that a method was called during the execution of a test (for the sake of argument, let's just say I can't really interrogate the state of the object after the call because the operation the method performs is not easy to see the effect of).

describe "#foo"
  it "should call 'bar' with appropriate arguments" do
    called_bar = false
    subject.stub(:bar).with("an argument I want") { called_bar = true }
    subject.foo
    expect(called_bar).to be_true
  end
end

What I want to know is: Is there a nicer syntax available than this? Am I missing some funky RSpec awesomeness that would reduce the above code down to a few lines? should_receive sounds like it should do this but reading further it sounds like that's not exactly what it does.

Answer 1

it "should call 'bar' with appropriate arguments" do
  expect(subject).to receive(:bar).with("an argument I want")
  subject.foo
end

Answer 2

In the new rspec expect syntax this would be:

expect(subject).to receive(:bar).with("an argument I want")