在方法調用時模仿Rspec中的錯誤消息.backtrace

Question

我有一個記錄錯誤的方法。它將一個錯誤消息作爲一個參數，但現在它需要一個完整的錯誤並在其上調用.backtrace。方法如下：

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

我想測試它，我無法弄清楚測試的語法。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 

我從RSPEC文檔嘗試各種組合，但我不斷收到對.backtrace方法絆倒了。我怎樣才能嘲笑這個錯誤消息，使.backtrace不會炸燬？在此先感謝您的幫助，並告知我是否需要提供任何信息。

編輯：對於類似的問題我用的解決方案是任何人：

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

我會做這樣的：

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