# Unit Tests of Models w/o Tables

**URL:** <https://www.ruby-forum.com/t/unit-tests-of-models-w-o-tables/119754>\
**Category:** Rails\
**Created:** [November 10, 2007, 12:29am UTC](https://www.ruby-forum.com/t/unit-tests-of-models-w-o-tables/119754 "2007-11-10T00:29:45Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![S-gw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ed655f/32.png) [@S-gw](https://www.ruby-forum.com/u/S-gw)\
**Post date:** [November 10, 2007, 12:29am UTC](https://www.ruby-forum.com/t/unit-tests-of-models-w-o-tables/119754/1 "2007-11-10T00:29:45Z")

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AWDWR focuses on unit tests for models with database tables. There’s  
no discussion for models w/o tables that I can see.

First attempts kept complaining about data tables not existing. I  
figured out this seems to come from the :fixtures line. Comment that  
out, and the test runs.

OK, but I do want to use test data, it’s just that it is not going to  
come from a database table. Is there some way to declare that the  
fixture file represents data that has nothing to do with database  
tables? Seems something like fixtures should be adaptable for  
simulating any data source.

Searching for some blog topics on this hasn’t been productive.

Certainly I can do my own setup that loads text files of sample data  
or pulls from a dummy web service as the case may be, but I just want  
to be sure that’s the intended solution.

– gw

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**Author:** ![S-gw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ed655f/32.png) [@S-gw](https://www.ruby-forum.com/u/S-gw)\
**Post date:** [November 10, 2007, 2:36am UTC](https://www.ruby-forum.com/t/unit-tests-of-models-w-o-tables/119754/2 "2007-11-10T02:36:28Z")

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Hi Greg,

I had to create unit tests for a model that was not in the database. I  
will share what I did, but my model was pretty much acted as a single  
object so there was not a big data requirement.

The unit test did not load any fixtures and so I just created new model  
objects as I needed them using a protected function like this (I was  
shown this technique in training from the BigNerd Ranch and I find it  
indispensable when writing tests now):

def create\_credit\_card(options={})  
CreditCard.new({  
:type =\> ‘VI’,  
:number =\> ‘4111111111111111’,  
:expires =\> ‘05/10’  
}.merge(options))  
end

I created tests like normal an just instantiated objects with the data I  
needed.

def test\_should\_require\_type  
card = create\_credit\_card(:type =\> ‘’)  
assert !card.valid?  
end

Does this make sense? I am not sure how well this would work if you  
need a lot of data. Good luck!

Peer

Greg W. wrote:

> AWDWR focuses on unit tests for models with database tables. There’s  
> no discussion for models w/o tables that I can see.
> 
> First attempts kept complaining about data tables not existing. I  
> figured out this seems to come from the :fixtures line. Comment that  
> out, and the test runs.
> 
> OK, but I do want to use test data, it’s just that it is not going to  
> come from a database table. Is there some way to declare that the  
> fixture file represents data that has nothing to do with database  
> tables? Seems something like fixtures should be adaptable for  
> simulating any data source.
> 
> Searching for some blog topics on this hasn’t been productive.
> 
> Certainly I can do my own setup that loads text files of sample data  
> or pulls from a dummy web service as the case may be, but I just want  
> to be sure that’s the intended solution.
> 
> – gw

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**Author:** ![S-gw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ed655f/32.png) [@S-gw](https://www.ruby-forum.com/u/S-gw)\
**Post date:** [November 10, 2007, 4:40am UTC](https://www.ruby-forum.com/t/unit-tests-of-models-w-o-tables/119754/3 "2007-11-10T04:40:32Z")

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On Nov 9, 2007, at 5:36 PM, Peer A. wrote:

> …I just created new model  
> objects as I needed them using a protected function like this (I was  
> shown this technique in training from the BigNerd Ranch and I find it  
> indispensable when writing tests now):

Yeah that could make sense for some cases. This particular one would  
need flexible data (it’s a config file parser). So, I have no problem  
using setup, or simply loadding data to start with by any means, just  
seemd weird that fixtures is dedicated to data table models.

Anyway, I’m having a lot more fundamental problem now in that I can’t  
seem to create instances of my model class w/in the test code.

Simplified version of my model…

class ConfigData

attr\_reader :configData

def initialize  
@configData = ‘’  
end

def loadFile(fileName)  
if FileTest::exist?(fileName)  
fileLines = IO.readlines(fileName)  
return fileLines  
end  
end

…lots of other methods…  
end

Even this simplified test complains…

require File.dirname( **FILE** ) + ‘/…/test\_helper’  
class ConfigData \< Test::Unit::TestCase  
def test\_loadFile  
cnfgData = ConfigData.new  
end  
end

What I get is a complaint about `initialize` having a “wrong number  
of arguments (0 for 1)” – but there are no arguments required.

I’m obviously missing the relationship of something somewhere, but  
I’m totally stumped.

– gw

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**Author:** ![S-gw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ed655f/32.png) [@S-gw](https://www.ruby-forum.com/u/S-gw)\
**Post date:** [November 10, 2007, 5:07am UTC](https://www.ruby-forum.com/t/unit-tests-of-models-w-o-tables/119754/4 "2007-11-10T05:07:59Z")

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On Nov 9, 2007, at 6:42 PM, Greg W. wrote:

> ```
> @configData = ''
> 
> ```
> 
> end
> 
> What I get is a complaint about `initialize` having a “wrong number  
> of arguments (0 for 1)” – but there are no arguments required.

After pulling nearly all my hair out (and I have a lot of it), I  
found the problem.

Notice this line:  
class ConfigData \< Test::Unit::TestCase  
should be  
class ConfigDataTest \< Test::Unit::TestCase

Aargh.

– gw

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**Author:** ![S-gw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ed655f/32.png) [@S-gw](https://www.ruby-forum.com/u/S-gw)\
**Post date:** [November 10, 2007, 6:06am UTC](https://www.ruby-forum.com/t/unit-tests-of-models-w-o-tables/119754/5 "2007-11-10T06:06:23Z")

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You might want to look into Mocha. Mocks can often put a finer point  
on what you’re trying to test – particularly if it’s not db-related.  
Check out: [Tags - James Mead](http://blog.floehopper.org/articles/tag/unit).

Consider this:

class ConfigDataTest \< Test::Unit::TestCase  
def LoadFileShouldOnlyReadFilesThatExist  
FileTest.stub!(:exist?).and\_return(false)  
@config = ConfigData.new  
assert what\_you\_expect\_when\_the\_file\_doesnt\_exist,  
@config.loadFile(‘abc.txt’)  
end

def LoadFileShouldReadFilesWhenTheyExist  
FileTest.stub!(:exist?).and\_return(true)  
IO.should\_receive(:readlines).once.and\_return([‘line1’, ‘line2’,  
‘line3’])  
@config = ConfigData.new  
assert\_equal 3, @config.LoadFile(‘test.txt’)  
end  
end

I’m not sure this code actually works, but if you see what I’m  
driving at, you can test a lot of different scenarios with not a lot  
of code.

Hope this helps.

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**Author:** ![S-gw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ed655f/32.png) [@S-gw](https://www.ruby-forum.com/u/S-gw)\
**Post date:** [November 10, 2007, 6:17am UTC](https://www.ruby-forum.com/t/unit-tests-of-models-w-o-tables/119754/6 "2007-11-10T06:17:29Z")

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Cool, I’ll check it out.

When I created the Unit test framework for Lasso I included a lot of  
explicit assertions that made it a lot clearer what was being tested  
for as well. ([www.l-unit.org](http://www.l-unit.org))

– gw

On Nov 9, 2007, at 9:05 PM, s.ross wrote:

> ```
> @config = ConfigData.new
> 
> ```
> 
> end
> 
> > > attr\_reader :configData  
> > > end  
> > > cnfgData = ConfigData.new  
> > > Notice this line:
> > 
> > >
> 
> >

– gw

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<div class="post-metadata">

**Author:** ![S-gw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ed655f/32.png) [@S-gw](https://www.ruby-forum.com/u/S-gw)\
**Post date:** [November 10, 2007, 7:25am UTC](https://www.ruby-forum.com/t/unit-tests-of-models-w-o-tables/119754/7 "2007-11-10T07:25:49Z")

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D’Oh. The assert in the second test case should have been:

assert\_equal 3, @config.LoadFile(‘test.txt’).size