Using RSpec how can I test the results of a rescue exception block

Question

I have a method that has a begin / rescue block in it. How do I test the rescue block using RSpec2?

class Capturer

  def capture
    begin
      status = ExternalService.call
      return true if status == "200"
      return false
    rescue Exception => e
      Logger.log_exception(e)
      return false
    end
  end

end

describe "#capture" do
  context "an exception is thrown" do
    it "should log the exception and return false" do
      c = Capturer.new
      success = c.capture
      ## Assert that Logger receives log_exception
      ## Assert that success == false
    end
  end
end

FYI see [Why is it bad style to `rescue Exception => e` in Ruby?](https://stackoverflow.com/q/10048173/211563). — Andrew Marshall, Apr 03 '14 at 00:04

Andrew Marshall · Accepted Answer · 2012-03-22T23:03:03.687

8

Use should_receive and should be_false:

context "an exception is thrown" do
  before do
    ExternalService.stub(:call) { raise Exception }
  end

  it "should log the exception and return false" do
    c = Capturer.new
    Logger.should_receive(:log_exception)
    c.capture.should be_false
  end
end

Also note that you should not be rescuing from Exception, but something more specific. Exception covers everything, which is almost definitely not what you want. At the most you should be rescuing from StandardError, which is the default.

edited Mar 22 '12 at 23:03

answered Mar 22 '12 at 20:48

Andrew Marshall

95,083
20
220
214

Yeah, but that doesn't raise the exception. – Nick Mar 22 '12 at 22:47
Your question doesn't really ask for that part, but I've updated my question with it anyway, as well as an additional note. – Andrew Marshall Mar 22 '12 at 23:03
It specifically asks **How do I test the rescue block using RSpec2?** – Nick Mar 22 '12 at 23:18
And your title specifically says "the results of the rescue block". It doesn't matter, does my updated answer help? – Andrew Marshall Mar 23 '12 at 00:38
It works, however the c.capture call needs to be wrapped in a lambda block. Thanks! – Nick Mar 23 '12 at 14:24

Using RSpec how can I test the results of a rescue exception block

1 Answers1

Linked