# Using AR and fixtures for testing \*outside\* of Rails?

**URL:** <https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042>\
**Category:** Ruby\
**Created:** [May 30, 2006, 11:34pm UTC](https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042 "2006-05-30T23:34:30Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [May 30, 2006, 11:34pm UTC](https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042/1 "2006-05-30T23:34:30Z")

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I’m working on a program that manipulates and stores a lot of data in  
a database via ActiveRecord. I’m having a heck of a time trying to  
write unit and functional tests for this program because I don’t have  
a reasonable way to reload the test db. I’d like to use the fixtures  
facility from Rails but so far I’ve failed at ripping it out and  
moving it to a non-Rails environment.

(BTW, I’m using the MockFS gem to test the filesystem portions of the  
code and I have to say it is working _brilliantly_. Many thanks to  
the author!)

Anyone have experience with this type of work? Care to share any tips  
on getting this to work?

Thanks very much.

cr

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [May 31, 2006, 3:36am UTC](https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042/2 "2006-05-31T03:36:35Z")

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On May 30, 2006, at 2:33 PM, removed\_email\_address@domain.invalid wrote:

> Anyone have experience with this type of work? Care to share any  
> tips on getting this to work?
> 
> Thanks very much.
> 
> cr

Hey-

```
I had to do the same thing to test an activerecord extension plugin

```

outside of rails. You can feel free to steal the test harness from  
my plugin:

[http://opensvn.csie.org/ezra/rails/ez\_where\_two/test/test\_helper.rb](http://opensvn.csie.org/ezra/rails/ez_where_two/test/test_helper.rb)

```
Thats the test_helper that loads activerecord with a database.yml

```

and then defines some models and loads the fixtures as well. Have a  
look around the plugin for the way I made this happen.

-Ezra

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [May 31, 2006, 3:49am UTC](https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042/3 "2006-05-31T03:49:08Z")

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On May 30, 2006, at 8:34 PM, Ezra Z. wrote:

> > (BTW, I’m using the MockFS gem to test the filesystem portions of
> 
> look around the plugin for the way I made this happen.  
> You’re a life saver! Thank you!

cr

Chuck R.  
removed\_email\_address@domain.invalid  
[www.familyvideovault.com](http://www.familyvideovault.com) (not yet live!)

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [May 31, 2006, 6:02pm UTC](https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042/4 "2006-05-31T18:02:19Z")

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On May 31, 2006, at 9:47 AM, Pistos C. wrote:

> problems using AR outside of Rails. I have been writing an  
> application  
> (IRC game) which uses AR with PostgreSQL, and I have had uncountable  
> problems due to the way AR connects to the database. I am constantly  
> hitting the maximum connection limit, and stray PostgreSQL child  
> processes are always being left around.
> 
> What DB are you using?

I’m using mysql 5.018 (latest AR, ruby 1.8.4 all on OSX 10.4.6) and  
so far I haven’t run into any problems like you describe. But since  
you’ve mentioned them, I’ll make sure my tests include detecting and  
handling those types of AR exceptions.

BTW, using Ezra’s sample code I’ve already gotten the fixtures  
loading in my tests. Excellent stuff. I’ll do a quick write-up after  
I’ve worked out all the kinks.

cr

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [May 31, 2006, 4:47pm UTC](https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042/5 "2006-05-31T16:47:17Z")

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unknown wrote:

> I’m working on a program that manipulates and stores a lot of data in  
> a database via ActiveRecord. I’m having a heck of a time trying to
> 
> Anyone have experience with this type of work? Care to share any tips  
> on getting this to work?

A bit away from your original topic (and perhaps this belongs on the  
Rails mailing list), but: I’d be interested to hear if you run into any  
problems using AR outside of Rails. I have been writing an application  
(IRC game) which uses AR with PostgreSQL, and I have had uncountable  
problems due to the way AR connects to the database. I am constantly  
hitting the maximum connection limit, and stray PostgreSQL child  
processes are always being left around.

What DB are you using?

Pistos

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [May 31, 2006, 10:24pm UTC](https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042/6 "2006-05-31T22:24:28Z")

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Pistos C. wrote:

> Rails mailing list), but: I’d be interested to hear if you run into any  
> problems using AR outside of Rails. I have been writing an application  
> (IRC game) which uses AR with PostgreSQL, and I have had uncountable  
> problems due to the way AR connects to the database. I am constantly  
> hitting the maximum connection limit, and stray PostgreSQL child  
> processes are always being left around.
> 
> What DB are you using?

Let me guess, your IRC game is multi-threaded? AR stores connections  
based on the Thread.current\_thread.id (or at least it does in  
1.13.2, things changed slightly in 1.14.2). I ran into this problem as  
well. If you are using AR 1.13.2 I can give you a fix,  
otherwise you’ll have to do it yourself or wait about a week for me to  
patch 1.14.2 (if it needs it).

Here is the code:

* * *

# Attempt to load active-record version, but if this dies, then don’t

complain

# Newer versions of rails seem to include VERSION by default, however

activerecord-1.13.2 doesn’t.  
begin ; require ‘active\_record/version’ ; rescue LoadError; end

# This includes changes to ActiveRecord 1.13.2

class ActiveRecord::Base

```
    # This is overridden because ActiveRecord 1.13.2 stores database 

```

connections based on the  
# Thread id. The processor uses a new thread for each new set of  
files to process.  
# We want the same connection to be used.  
#  
# Version 1.14.2 no longer has the class variable  
@@connection\_cache, so we should  
# not redefine this method if we are at or above that version.  
if ActiveRecord::VERSION::STRING \< ‘1.14.2’  
def self.connection  
@@connection\_cache[123456][name] ||= retrieve\_connection  
end  
end  
end

* * *

How this helps,

Zach

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [June 1, 2006, 4:27pm UTC](https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042/7 "2006-06-01T16:27:03Z")

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zdennis wrote:

> Let me guess, your IRC game is multi-threaded? AR stores connections

I think you’re onto something there… 🙂

> based on the Thread.current\_thread.id (or at least it does in  
> 1.13.2, things changed slightly in 1.14.2). I ran into this problem as  
> well. If you are using AR 1.13.2 I can give you a fix,  
> otherwise you’ll have to do it yourself or wait about a week for me to  
> patch 1.14.2 (if it needs it).

I happen to be specifically require\_gem’ing 1.13.2 for the game, solely  
because stuff after 1.13.2 caused me even worse problems…

> Here is the code:  
> How this helps,
> 
> Zach

I put the code in place, and it seems to be helping, based on  
preliminary testing. It’s too early to tell for sure, though, so I will  
keep you posted. Thanks for this patch. If it works, it will surely be  
a great boon to the game. 🙂

Pistos

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [June 2, 2006, 5:35pm UTC](https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042/8 "2006-06-02T17:35:17Z")

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zdennis wrote:

> You can actually test this in a unit test. =)  
> There is also a method on ActiveRecord::Base called ‘active\_connections’  
> There is another method on ActiveRecord::Base called  
> ‘threaded\_connections’ which returns true or false (by default true). I  
> [much snippage above]

Well, unit test or not, the evidence is here:

# ps aux | grep postgres | grep idle | grep -v grep | wc -l

22

## template1=# select count(\*) from pg\_stat\_activity where current\_query = ‘’ and query\_start \< NOW() - ‘2 hours’::INTERVAL; count

```
18

```

The good news is, some of the processes DO seem to go away on their own.  
The bad news is, some stay around for some time:

## template1=# select count(\*) from pg\_stat\_activity where current\_query = ‘’ and query\_start \< NOW() - ‘20 hours’::INTERVAL; count

```
 2

```

As well, I haven’t yet actually gotten the “too many connections” error  
from PostgreSQL, so that is somewhat encouraging.

Furthermore, we should bear in mind that some of these connections are  
from the companion Rails site that works with the game (shared DB). I’m  
not sure how to distinguish Rails connections from game connections.  
I’m using FastCGI, and, as far as I know, that keeps processes alive.

If you ever find time, maybe we can work together on the problem via  
IRC? I’m on FreeNode often with the nick Pistos.

Pistos

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [June 2, 2006, 5:02am UTC](https://www.ruby-forum.com/t/using-ar-and-fixtures-for-testing-outside-of-rails/62042/9 "2006-06-02T05:02:22Z")

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Pistos C. wrote:

> > well. If you are using AR 1.13.2 I can give you a fix,
> > 
> > Zach
> 
> I put the code in place, and it seems to be helping, based on  
> preliminary testing. It’s too early to tell for sure, though, so I will  
> keep you posted. Thanks for this patch. If it works, it will surely be  
> a great boon to the game. 🙂

Pistos,

You can actually test this in a unit test. =)

def test\_connection\_count  
2.times do  
Thread.new{ Job.find\_all }  
end  
assert\_equal 1, ActiveRecord::Base.module\_eval( “@@connection\_cache”  
).size, “Too many connections are being created!”  
end

There is also a method on ActiveRecord::Base called ‘active\_connections’  
and it seems to always return 1, however if you actually  
do the module\_eval for @@connection\_cache, you will see there are more  
connections (that are potentially active) then  
‘active\_connections’ returns.

There is another method on ActiveRecord::Base called  
‘threaded\_connections’ which returns true or false (by default true). I  
was  
hoping that if you set it to false, it would fix the problem, but  
setting it to false doesn’t seem to do anything for this  
particular problem.

I am gone for the weekend, if you find anything else out please post so  
I can read when I get back, otherwise I’ll dive in over  
the weekend to AR and find out what I can (and to see if AR 1.14.2 has  
this problem)

Have a good weekend Pistos!

Zach  
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