CODEWITHSUNDEEP
ruby-on-railsrubyunit-testingrspec
ruby_newbie
ruby_newbie

Reputation: 3285

mocking an error message in Rspec when method calls .backtrace

i have a method that logs errors. It was taking an error message as a parameter but now it takes an entire error and calls .backtrace on it. The method is below: 

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

I am trying to test it and I cant figure out the syntax for the test. WHat I had before is: 

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

I have tried various combinations from the rSpec docs but I keep getting tripped up on the .backtrace method. How can I mock this error message so that .backtrace doesn't blow up? Thanks in advance for your help and let me know if I need to give anymore information.

Edit: For anyone with a similar problem the solution I used was: 

 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

Upvotes: 1

Views: 491

Answers (1)

spickermann
spickermann

Reputation: 106882

I would do it like this: 

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

Upvotes: 1

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