Scenario

I'm writing a library (no Ruby on Rails) for which I'd like to have very detailed Cucumber features. This especially includes describing errors/exceptions that should be thrown in various cases.

Example

The most intuitive way to write the Cucumber steps would probably be something like

When I do something unwanted
Then an "ArgumentError" should be thrown

Problem

There are two issues I have to address:

  1. The first step should not fail when an exception is thrown.
  2. The exception that the first step throws should be accessible to the second step in order to do some assertion magic.

Unelegant And Cumbersome Solution

The best approach I've been able to come up with is caching the exception in the first step and putting it into an instance variable that the second step can access, like so:

When /^I do something unwanted$/ do
  begin
    throw_an_exception!
  rescue => @error
  end
end

Then /^an "(.*)" should be thrown$/ do |error|
  @error.class.to_s.should == error
end

However, this makes the first step more or less useless in cases where I don't want it to fail, and it requires an instance variable, which is never a good thing.

So, can anyone help me out with an at least less cumbersome solution? Or should I write my features differently anyway? Any help would be much appreciated.

ruby exception cucumber
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