# Unit test problem with time update

**URL:** <https://www.ruby-forum.com/t/unit-test-problem-with-time-update/165309>\
**Category:** Rails\
**Created:** [April 12, 2009, 12:43am UTC](https://www.ruby-forum.com/t/unit-test-problem-with-time-update/165309 "2009-04-12T00:43:45Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![ps\_gem](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ac8455/32.png) [@ps\_gem](https://www.ruby-forum.com/u/ps_gem)\
**Post date:** [April 12, 2009, 12:43am UTC](https://www.ruby-forum.com/t/unit-test-problem-with-time-update/165309/1 "2009-04-12T00:43:45Z")

</div>

Hi all, I am new to Ruby on Rails and struggling to finish my class  
project.  
I have problem with unit testing, if any body could help.

## I have a function that updates ‘feeds’ table. It has a columns: id, feeddata, lastupdate. feedupdate.

The function in method feed.rb is as follows:

## def Feed.updatefeed(feed\_id) @u = Feed.find(feed\_id) #response=fetch(@u.sourcelink) #@u.feeddata=response.body @u.lastupdate=Time.now @u.save! end

my test feed\_test.rb is as follows:

require File.dirname( **FILE** ) + ‘/…/test\_helper’

class FeedTest \< ActiveSupport::TestCase

# Replace this with your real tests.

fixtures :feeds

def test\_truth  
assert true  
end

def test\_updatefeed  
feed1 = Feed.find(:first,:conditions=\>[“id=?”,12])  
Feed.updatefeed(feed1.id)  
assert\_equal(Time.now, feed1.lastupdate)  
end

## end

fixture:

feed\_1:  
id: 1  
sourcelink: [http://sports.yahoo.com/ncaaf/teams/aad/ical.ics](http://sports.yahoo.com/ncaaf/teams/aad/ical.ics)  
feeddata: testdata  
lastupdate: 2009-02-17 22:42:25  
used: 1  
…

## feed\_12: id: 12 sourcelink: [http://icalx.com/public/wesleyrhall/Astronomy.ics](http://icalx.com/public/wesleyrhall/Astronomy.ics) feeddata: testdata lastupdate: 2009-02-17 22:42:25 used: 1

My ‘updatefeed’ function is working on application well. But my test  
doesn’t show the updated ‘lastupdated’ column date but only the value in  
fixture. Shouldn’t the fixture value be updated on execution and after  
comparison set it back?

---

<div class="post-metadata">

**Author:** ![ps\_gem](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ac8455/32.png) [@ps\_gem](https://www.ruby-forum.com/u/ps_gem)\
**Post date:** [April 12, 2009, 1:53am UTC](https://www.ruby-forum.com/t/unit-test-problem-with-time-update/165309/2 "2009-04-12T01:53:21Z")

</div>

On Apr 11, 11:43 pm, Ps\_gem Sh\_gem [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> My ‘updatefeed’ function is working on application well. But my test  
> doesn’t show the updated ‘lastupdated’ column date but only the value in  
> fixture. Shouldn’t the fixture value be updated on execution and after  
> comparison set it back?

If you do SomeMode.find(123) twice, you’ll get back two separate  
objects (that both correspond to the row in the database with id 123.

The way you’ve written your code, the updatefeed method loads a  
separate copy of the feed and updates that, but you do your assertion  
on a separate copy of it. You would need to reload it to see the  
change you made. It’s also a bit odd that you’ve made updatefeed a  
class method - looks much more like an instance method to me - you  
also probably don’t want to be using an instance variable in there.  
Lastly, if you table has an updated\_at column, rails will fill that in  
for you everytime you save the object.

Fred

---

<div class="post-metadata">

**Author:** ![ps\_gem](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ac8455/32.png) [@ps\_gem](https://www.ruby-forum.com/u/ps_gem)\
**Post date:** [April 12, 2009, 5:53am UTC](https://www.ruby-forum.com/t/unit-test-problem-with-time-update/165309/3 "2009-04-12T05:53:03Z")

</div>

Ps\_gem Sh\_gem wrote:

> Hi all, I am new to Ruby on Rails and struggling to finish my class  
> project.  
> I have problem with unit testing, if any body could help.

Professor Phlip will now dispense some tips.

> I have a function that updates ‘feeds’ table. It has a columns: id,  
> feeddata, lastupdate. feedupdate.

Don’t dupe the name of feeds into the feeds fields - feeddata should be  
data.  
And reconsider ‘data’ - what is the _intent_ of its variable? Where will  
it come  
out into the world and do something?

Next, “script/generate model” will generate created\_on and updated\_on  
automatically for you. Maybe they are already there; and maybe this  
assignment  
intends to see if you will use them.

> The function in method feed.rb is as follows:
> 
> def Feed.updatefeed(feed\_id)

update\_feed. The goal is to match natural language whenever possible, so  
break  
words up with underbars.

> ```
> @u = Feed.find(feed_id)
> 
> ```

I don’t think you will use @u with the same value in any other method  
(also, you  
are in a class method, so the @u lives in essentially the metaclass of  
the Feed  
class, or something like that). Call it ‘feed’.

> ```
> #response=fetch(@u.sourcelink)
> #@u.feeddata=response.body
> 
> ```

Put spaces around binary operators like =.

> ```
> @u.lastupdate = Time.now
> @u.save!
> 
> ```
> 
> ## end
> 
> my test feed\_test.rb is as follows:
> 
> class FeedTest \< ActiveSupport::TestCase
> 
> # Replace this with your real tests.

Please delete all code that is not useful - including that comment, and  
including the test\_truth stub.

> fixtures :feeds
> 
> def test\_truth  
> assert true  
> end
> 
> def test\_updatefeed  
> feed1 = Feed.find(:first,:conditions=\>[“id=?”,12])  
> Feed.updatefeed(feed1.id)  
> assert\_equal(Time.now, feed1.lastupdate)

After you .reload the feed1, you will discover you cannot compare floats  
for  
equality. A time is a float, and the time will increment by a  
microsecond or so  
after the “money line” fires.

Try this:

```
   feed = feeds(feed_1)
   feed.update_attribute :updated_at, 1.hour.ago # spike
   Feed.update_feed(feed.id)
   feed.reload
   assert 1.second.ago < feed.updated_on &&
             feed.updated_on < 1.second.from_now

```

Note I dropped the (). That is to rub the nose of every Java user how  
easy Ruby  
makes unit tests, especially assertions.

My assertion is a variation on a common theme - assert\_close, or  
assert\_in\_delta. The point is to ensure a floating point number falls  
inside a  
tiny range; larger than common software math rounding errors, and larger  
than  
the time one test takes to execute. It still uses wall-clock time, not  
CPU time,  
so if your CPUs were loaded down with work the assertion might fail, but  
tests  
typically have the computer to themselves so we won’t worry about that.

> end
> 
> end

> feed\_1:  
> id: 1

If your Rails version is \> 2.0.0, drop the id: 1, and use automatically  
generated ids.

> sourcelink: [http://sports.yahoo.com/ncaaf/teams/aad/ical.ics](http://sports.yahoo.com/ncaaf/teams/aad/ical.ics)

If the feed deals with yahoo, don’t name it :feed\_1. Name it :yahoo

–  
Phlip

---

<div class="post-metadata">

**Author:** ![ps\_gem](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/ac8455/32.png) [@ps\_gem](https://www.ruby-forum.com/u/ps_gem)\
**Post date:** [April 12, 2009, 8:43pm UTC](https://www.ruby-forum.com/t/unit-test-problem-with-time-update/165309/4 "2009-04-12T20:43:10Z")

</div>

[http://sports.yahoo.com/ncaaf/teams/aad/ical.ics](http://sports.yahoo.com/ncaaf/teams/aad/ical.ics) was just an example of  
a link to download iCalendar feed, it can be from anywhere so I used  
feed\_1, feed\_2…feed\_n for generic term.

This worked:

def test\_updatefeed  
feed = feeds(:feed\_1)  
feed.update\_attribute :lastupdate, 1.hour.ago # spike  
Feed.updatefeed(feed.id)  
feed.reload  
assert 1.second.ago \< feed.lastupdate &&  
feed.lastupdate \< 1.second.from\_now  
end

Thanks