Narrow the rescued exception to avoid catching class evaluation errors that has nothing to to with the association.

Example:

    /Users/weppos/.rvm/gems/ruby-1.8.7-p330/gems/couchrest_model-1.0.0/lib/couchrest/model/associations.rb:29:in `belongs_to': Unable to convert class name into Constant for Document#dossier (RuntimeError)

although the real error is

    /Users/weppos/Projects/working/.../app/models/user.rb:56: undefined method `validates_uniqueness_of' for User:Class (NoMethodError)

lib/couchrest/model/associations.rb

@@ -25,8 +25,8 @@ module CouchRest
 
           begin
             opts[:class] = opts[:class_name].constantize
-          rescue
-            raise "Unable to convert class name into Constant for #{self.name}##{attrib}"
+          rescue NameError
+            raise NameError, "Unable to convert class name into Constant for #{self.name}##{attrib}"
           end
 
           prop = property(opts[:foreign_key], opts)

spec/couchrest/assocations_spec.rb

@@ -44,11 +44,11 @@ describe "Assocations" do
     end
 
     it "should raise error if class name does not exist" do
-      lambda {
+      lambda do
         class TestBadAssoc < CouchRest::Model::Base
           belongs_to :test_bad_item
         end
-      }.should raise_error
+      end.should raise_error(NameError, /TestBadAssoc#test_bad_item/)
     end
 
     it "should allow override of foreign key" do