When an exception is raised during rendering of a view it is wrapped inside an ActionView::Template::Error which is then reraised.

This leads to unhelpful failure messages in view specs, along the lines of

contact/index.html.haml renders a form to send feedback
     Failure/Error: it "renders a form to send feedback" do render
     ActionView::Template::Error
     # ./app/views/contact/index.html.haml:19
     # ./spec/views/contact/index.html.haml_spec.rb:10:in `block (2 levels) in '

This little monkey patch

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module RSpec
  module Core
    class Example
      def set_exception(exception)
        if exception.is_a?(ActionView::Template::Error)
          @exception ||= exception.original_exception
        else
          @exception ||= exception
        end
      end
    end
  end
end

ensures that the original exception is the one that is displayed.