Rspec 断言没有意义：双重收到带有 <message> 的意外消息

Question

这是一个可重复性极低的示例，您可以复制它并使用最新版本的gem install rspec 运行它。

#class Bar
#  def run_bar(a:, b:)
#    return
#  end
#end

def foo(bar)
  if bar != nil
    bar.run_bar(a: "test", b: {})
  end
end

describe 'foo' do
  it 'runs bar' do
    bar_stub = double('bar')
    foo(bar_stub)
    expect(bar_stub).to receive(:run_bar).with(a: "test", b: {})
  end
end

我认为这个测试是有道理的，但是当我运行它时，它没有说它收到了一条意外消息，该消息实际上是从实际调用中复制粘贴的。

% rspec test.rb
F

Failures:

  1) foo runs bar
     Failure/Error: bar.run_bar(a: "test", b: {})
       #<Double "bar"> received unexpected message :run_bar with ({:a=>"test", :b=>{}})
     # ./test.rb:9:in `foo'
     # ./test.rb:16:in `block (2 levels) in <top (required)>'

Finished in 0.00812 seconds (files took 0.09453 seconds to load)
1 example, 1 failure

Failed examples:

rspec ./test.rb:14 # foo runs bar

如果重要，这里是版本。

% rspec --version
RSpec 3.10

Answer 1

哦，我想我刚刚意识到expect 必须在代码实际运行之前出现。

#class Bar
#  def run_bar(a:, b:)
#    return
#  end
#end

def foo(bar)
  if bar != nil
    bar.run_bar(a: "test", b: {})
  end
end

describe 'foo' do
  it 'runs bar' do
    bar_stub = double('bar')
    expect(bar_stub).to receive(:run_bar).with(a: "test", b: {})
    foo(bar_stub)
  end
end