Set_fixture_class works on individual test, but test suite fails

dubstep · November 14, 2011, 9:49pm

Hi all,

I have a bug in my code that I have been unable to track down that
deals with the set_fixture_class statement. Basically,
set_fixture_class (and my tests) are working fine when I test one
controller in isolation, but they are failing when I run all my
controller specs together.

My project use both a local database and Amazon Rds, and the tables on
Amazon are namespaced with Rds::TableName.

My controller spec looks something like:

describe MyFirstController do
set_fixture_class :users => Rds::User

describe ‘my test’ do
it ‘should do something’ do
joe = users(:joe)
end
end
end

This works fine when running just this controller’s spec. But when I
run all the controller specs, the error I get is:

Failure/Error: joe = users(:joe)
FixtureClassNotFound:
No class attached to find.

I have isolated the problem to the interaction between two controller
specs, MyFirstController (which contains set_fixture_class) and
MySecondController (which does not contain set_fixture_class). When
the tests for MyFirstController are run before the tests for
MySecondController, everything works fine. But when the order is
reversed, I get the above errors.

Any ideas on what I might be able to do to fix this (besides requiring
MyFirstController to run first)?

Stephen_Kessler · November 15, 2011, 6:09am

On Nov 8, 2011, at 10:52 AM, Stephen Kessler wrote:

My controller spec looks something like:

describe MyFirstController do
set_fixture_class :users => Rds::User

set_fixture_class is defined in rails:

github.com

rails/rails/blob/main/activerecord/lib/active_record/fixtures.rb#L745


      
            else
              @model_class = class_name.safe_constantize if class_name
            end
          end
          
          
def ignored_fixtures=(base)
            @ignored_fixtures =
                case base
                when Array
                  base
                when String
                  [base]
                else
                  []
                end
          
          
  @ignored_fixtures << "DEFAULTS" unless @ignored_fixtures.include?("DEFAULTS")
            @ignored_fixtures.compact
          end
          
          
# Loads the fixtures from the YAML file at +path+.

It’s a class method that interacts with a class_attribute defined in the
same file:

github.com

rails/rails/blob/main/activerecord/lib/active_record/fixtures.rb#L727


      
          
          
# Returns a hash of rows to be inserted. The key is the table, the value is
          # a list of rows to insert to that table.
          def table_rows
            # allow specifying fixtures to be ignored by setting `ignore` in `_fixture` section
            fixtures.except!(*ignored_fixtures)
          
          
  TableRows.new(
              table_name,
              model_class: model_class,
              fixtures: fixtures,
            ).to_hash
          end
          
          
private
            def model_class=(class_name)
              if class_name.is_a?(Class) # TODO: Should be an AR::Base type class, or any?
                @model_class = class_name
              else
                @model_class = class_name.safe_constantize if class_name
              end

This means that once it’s set, it’s set, which explains the behavior
you’re seeing.

You can get around this by storing the original setting and restoring it
in an after block:

before do
@orig = self.class.fixture_class_names[:users]
self.class.fixture_class_names[:users] = Rds::User
end

after do
self.class.fixture_class_names[:users] = Rds::User
end

This is very invasive as it interacts directly with variables instead of
APIs, so it might easily break in a future version of rails, but I’m not
sure what better option you have. It’s not really designed to be used
how you’re using it.

HTH,
David