Hi folks,
I've been unhappy with routing specs for a long time now and last night when
updating some old 1.3 specs for 2.0 I decided to see if I could come up with
something that didn't make me feel unhappy.
Principal causes of unhappiness:
1. Historically we had "route_for" and "params_from", which felt awfully
repetitive because we ended up doing:
route_for(lengthy_hash_of_params).should ==
string_or_hash_describing_destination
params_from(list_describing_destination).should == lengthy_hash_of_params
Of course, it was worse than that in practice because those two lines usually
appeared in separate example blocks with the associated boilerplate. It felt
like a lot of work for testing such a simple thing. It also felt irritating to
have to repeat basically the same thing twice but in a different order.
2. So then RSpec gave us "route_to", which is a wrapper for Rails'
"assert_routing"; being a bi-directional test that encompasses the function of
both "assert_recognizes" and "assert_generates", this allows us to avoid some,
or even all, of the repetition:
{ :get => 'foo' }.should route_to(:controller => 'foo', :action => 'index')
The unhappiness here comes from three causes:
One is that { :get => 'foo' } feels inconsistent with other places in RSpec
like controller specs where "get" is a method, so we can do things like "get
'thing'".
The second issue is that the "to" in "route_to" feels misleadingly
uni-directional when in reality it is a bi-directional test.
The third issue is that for routes which don't actually have that
bi-directional mapping, "route_to" can't be used and we must instead drop down
to Rails' assert_recognizes() and/or assert_generates() methods, or wrap them
using our own matchers.
So I thought about what I would rather be writing and in my first cut came up
with this:
describe ArticlesController do
describe 'routing' do
example 'GET /wiki' do
get('/wiki').should map_to(:controller => 'articles', :action =>
'index')
get('/wiki').should map_from(:controller => 'articles', :action =>
'index')
articles_path.should == '/wiki'
end
end
end
Things to note:
- make the bi-directionality of the mapping explicit by having separate
"map_to" and "map_from" lines.
- for ease of readability and writability, keep the order as "method -> path ->
destination" for both assertions by using "to" and "from", rather than swapping
the order around
- "map" here is the right verb because we've always used that language to talk
about how a given URL "maps to" a given controller#action. And remember how in
the router DSL prior to Rails 3 everything in config/routes.rb started with
"map"?
- I've tacked a test for the "articles_path" URL helper in there, because as a
user of the Rails router I generally want to know two things: firstly, that
requests get mapped to the appropriate controller#action; and secondly, that
when I generate URLs (almost exclusively with named helpers; I use "url_for" in
only 4 places in my entire app) that they take me where I think they take me.
In the end, however, I moved this into a separate "describe 'URL helpers'"
block.
- conscious use of "example" rather than "it" because I want my specs to be
identified as "ArticlesController routing GET /wiki" and not
"ArticlesController routing recognizes and generates #index".
- the repetition is a conscious choice because I value readability/scannability
over DRYness-at-all-costs, especially in specs; the following is more DRY, for
example, but less readable/scannable:
path = '/wiki'
destination = { :controller => 'articles, :action => 'index' }
get(path).should map_to(destination)
get(path).should map_from(destination)
So I went ahead and converted a bunch of specs to this syntax and found that,
surprise, surprise, in an application like this one where almost everything
consists of a "standard" RESTful resource, over 90% of routes were testable in
the bi-directional sense and in a typical routing spec file I needed to use
"map_to" with no corresponding "map_from" for only one or two cases. So I
needed a new method that meant "map_to_and_from".
Funnily, I just can't decide on a name for this method. As a placeholder I am
just using "map" for now:
get('/wiki').should map(:controller => 'articles', :action => 'index')
But others I have tried are:
get('/wiki').should map_as(:controller => 'articles', :action => 'index')
get('/wiki').should map_via(:controller => 'articles', :action => 'index')
get('/wiki').should map_with(:controller => 'articles', :action => 'index')
get('/wiki').should map_to_and_from(:controller => 'articles', :action =>
'index')
get('/wiki').should map_both(:controller => 'articles', :action => 'index')
get('/wiki').should map_both_ways(:controller => 'articles', :action =>
'index')
get('/wiki').should have_routing(:controller => 'articles', :action =>
'index')
get('/wiki').should have_route(:controller => 'articles', :action => 'index')
get('/wiki').should be_route(:controller => 'articles', :action => 'index')
get('/wiki').should be_routing(:controller => 'articles', :action => 'index')
get('/wiki').should route_as(:controller => 'articles', :action => 'index')
get('/wiki').should route_via(:controller => 'articles', :action => 'index')
get('/wiki').should route(:controller => 'articles', :action => 'index')
get('/wiki').should <=> (:controller => 'articles', :action => 'index')
get('/wiki').should > (:controller => 'articles', :action => 'index') # map_to
get('/wiki').should < (:controller => 'articles', :action => 'index') #
map_from
If anybody has a suitable suggestion please let me know.
In the meantime, here is an example of a spec file that has been converted to
use this new "API":
http://gist.github.com/464081
It also includes the supporting code that adds these new "map", "map_to",
"map_from" matchers, and the "get", "post", "put" and "delete" methods. All of
this for Rails 3/RSpec 2 only.
I'm going to convert more routing specs and see if any more changes are needed
to handle edge cases, but for a first cut I am pretty happy with the results,
apart from my inability to decide on the right name for the bi-directional
"map" matcher.
Cheers,
Wincent
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