在方法调用时模仿Rspec中的错误消息.backtrace

Question

我有一个记录错误的方法。它将一个错误消息作为一个参数，但现在它需要一个完整的错误并在其上调用.backtrace。方法如下：

def log_error(error) 
    puts error.backtrace 
    puts "RECONCILE_TAX_RATES [#{Time.now}] ERROR [#{error.message}]" 
    end 

我想测试它，我无法弄清楚测试的语法。我收到的是：

it 'logs errors' do 
    time = "Tue, 16 Sep 2014 20:18:19 UTC +00:00" 
    Timecop.freeze(time) do 
     tax_reconciler = TaxReconciler.new 
     error_message = "I'm sorry, Dave. I'm afraid I can't do that." 
     expected = "RECONCILE_TAX_RATES [2014-09-16 20:18:19 UTC] ERROR [I'm sorry, Dave. I'm afraid I can't do that.]" 

     STDOUT.should_receive(:puts).with(expected) 
     tax_reconciler.log_error(error_message) 
    end 
    end 

我从RSPEC文档尝试各种组合，但我不断收到对.backtrace方法绊倒了。我怎样才能嘲笑这个错误消息，使.backtrace不会炸毁？在此先感谢您的帮助，并告知我是否需要提供任何信息。

编辑：对于类似的问题我用的解决方案是任何人：

it 'logs errors' do 
    time = "Tue, 16 Sep 2014 20:18:19 UTC +00:00" 
    Timecop.freeze(time) do 
     expected = "RECONCILE_TAX_RATES [2014-09-16 20:18:19 UTC] ERROR [I'm sorry, Dave. I'm afraid I can't do that.]" 
     tax_reconciler = TaxReconciler.new 
     begin 
     raise "I'm sorry, Dave. I'm afraid I can't do that." 
     rescue => error_message 
     STDOUT.should_receive(:puts).with(expected) 
     STDOUT.should_receive(:puts).with(error_message.backtrace) 
     tax_reconciler.log_error(error_message) 
     end 
    end 
    end 

Answer 1

我会做这样的：

describe '#log_error' do 
    let(:time) { 'Tue, 16 Sep 2014 20:18:19 UTC +00:00' } 
    let(:message) { 'The message' } 
    let(:error) { double(:message => message, :backtrace => []) } 
    let(:line) { 'RECONCILE_TAX_RATES [2014-09-16 20:18:19 UTC] ERROR [The message]' } 

    subject(:tax_reconciler) { TaxReconciler.new } 

    before { allow(STDOUT).to receive(:puts) } 

    it 'logs errors' do 
    Timecop.freeze(time) do 
     tax_reconciler.log_error(error) 
     expect(STDOUT).to have_receive(:puts).with(line) 
    end 
    end 
end