[rspec-users] [rspec] loading specs as an object model without running them

David Chelimsky dchelimsky at gmail.com
Wed Apr 29 07:41:59 EDT 2009

On Wed, Apr 29, 2009 at 6:09 AM, Marty Andrews <marty at martyandrews.net> wrote:
> On 29/04/2009, at 8:54 PM, David Chelimsky wrote:
>> On Wed, Apr 29, 2009 at 1:23 AM, Marty Andrews <marty at martyandrews.net>
>> wrote:
>>> I'd like to load all of my examples into memory without actually
>>> running them, so I can traverse the object tree and get descriptions
>>> etc.  I'm finding it tricky to figure out how to do that though.
>>> There seems to be an inherent assumption in the framework that that
>>> examples will actually run.
>>> So basically, I want to do something like this:
>>> examples = load_examples_without_running
>>> examples.each {|example| puts example.description}
> [snip]
>> As for getting a handle on the objects, this is something that is not
>> really baked into RSpec, but will definitely be baked into rspec-2.0.
>> Work on this will start later this year (probably not until after the
>> rspec book is off to print). Goals for it include a very clean
>> separation of the DSL and the underlying object model and a very
>> lightweight runner.
>> So in the short run, your best option is to use --dry-run and
>> understand that you only get value out of it if you write docstrings
>> for all of your examples.
> Ok.  It's actually a bit more complicate than that.  Let me give you an
> insight into where I'm headed.
> I'm working into a big corporate in Australia, and they are demanding
> traceability of tests back to requirements.  I'm already using Mingle to
> manage story cards, and I'm hoping to let the testers build in the
> traceability via code.  So I've got a Mixin to the examples so that I can
> declare the id of the story that the test maps to.  It looks something like
> this:
> describe FunctionalArea do
>  it "automates some acceptance test declared on a story" do
>    traces_to_story 35
>    # test implementation
>  end
> end
> So now, I want to be able to walk the object tree, getting the descriptions
> *and* the story id's.  Mingle has a nice RESTful API that I've already used
> to slurp up detail about stories.  Now I just want to wire in this last bit
> of information to tick the traceability box without any human needing to do
> the work.
> I'll have a look at the --dry-run option and see where it gets me.  If
> you've got any more tips, let me know.  I'll send in a code snippet if I
> manage to get it going :)

There *is* something you can *almost* use for this, but it's
incomplete at the moment. RSpec let's you write your own output
formatters, which receive messages for every example group and example
as they are run. Currently, the object passed to example_started (and
a few other methods) is an ExampleGroupProxy, which includes an
options hash passed to the example. So if you do this:

it "automates some acceptance test declared on a story",
    :traces_to_story => 25 do
# ...

Then you could do stuff like:

def example_started(example_proxy)

This should solve your problem assuming that you have docstrings for
all of your examples. The big missing piece at this moment is that the
ExampleGroupProxy (passed to example_group_started) doesn't include
the options hash, but I'll happily add that tonight.

To see this in action, try this:

* in options_formatter.rb

require 'spec/runner/formatter/base_text_formatter'

class OptionsFormatter < Spec::Runner::Formatter::BaseTextFormatter
  def example_started(proxy)
    puts proxy.options.inspect unless proxy.options.empty?

* in example_spec.rb

require 'spec'

describe "example" do
  it "supports options", :like => 'these' do
    # no need for anything here

Now, on the command line:

$ spec --require options_formatter.rb example_spec.rb --format OptionsFormatter
{:like => 'these'}

Formatter API is here:

Let me know if this is a good direction for you and I'll add the
options hash to the example group proxy.


> -- Marty
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