Ruby RSpec：每次指定对具有不同参数的方法的多次调用

在rspec(1.2.9)中，指定一个对象每次都会收到对一个具有不同参数的方法的多个调用的正确方法是什么？

因为这个令人困惑的结果，我问:

describe Object do

  it "passes, as expected" do
    foo = mock('foo')
    foo.should_receive(:bar).once.ordered.with(1)
    foo.should_receive(:bar).once.ordered.with(2)
    foo.bar(1)
    foo.bar(2)
  end

  it "fails, as expected" do
    foo = mock('foo')
    foo.should_receive(:bar).once.ordered.with(1) # => Mock "foo" expected :bar with (1) once, but received it twice
    foo.should_receive(:bar).once.ordered.with(2)
    foo.bar(1)
    foo.bar(1)
    foo.bar(2)
  end

  it "fails, as expected" do
    foo = mock('foo')
    foo.should_receive(:bar).once.ordered.with(1)
    foo.should_receive(:bar).once.ordered.with(2)
    foo.bar(2) # => Mock "foo" received :bar out of order
    foo.bar(1)
  end

  it "fails, as expected, but with an unexpected message" do
    foo = mock('foo')
    foo.should_receive(:bar).once.ordered.with(1)
    foo.should_receive(:bar).once.ordered.with(2)
    foo.bar(1)
    foo.bar(999) # => Mock "foo" received :bar with unexpected arguments
                 # =>   expected: (1)
                 # =>         got (999)
  end

end

我希望最后一条失败消息是"预期的:(2)"，而不是"预期的(1)".我是否错误地使用了rspec？