ruby - RSpec:每次指定对具有不同参数的方法的多次调用

Question

在 rspec (1.2.9) 中，指定一个对象每次都会收到对一个方法的多次调用的正确方法是什么？

我问是因为这个令人困惑的结果:

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

我预计最后一条失败消息是“预计:(2)”，而不是“预计 (1)”。我是否错误地使用了 rspec？

Answer 1

类似于此question .推荐的解决方案是调用as_null_object 来避免消息的混淆。所以:

describe Object do
  it "fails, as expected, (using null object)" do
    foo = mock('foo').as_null_object
    foo.should_receive(:bar).once.ordered.with(1)
    foo.should_receive(:bar).once.ordered.with(2)
    foo.bar(1)
    foo.bar(999) # => Mock "foo" expected :bar with (2) once, but received it 0 times
  end
end

输出与您的第二种情况(即“预期 2 但得到 999”)不同，但它确实表明没有达到预期。