# How do I patch Test::Unit?

**URL:** <https://www.ruby-forum.com/t/how-do-i-patch-test-unit/114694>\
**Category:** Ruby\
**Created:** [September 17, 2007, 1:24pm UTC](https://www.ruby-forum.com/t/how-do-i-patch-test-unit/114694 "2007-09-17T13:24:18Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![jeff](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jeff](https://www.ruby-forum.com/u/jeff)\
**Post date:** [September 17, 2007, 1:24pm UTC](https://www.ruby-forum.com/t/how-do-i-patch-test-unit/114694/1 "2007-09-17T13:24:18Z")

</div>

I’ve finally found some time to dig into one of my favorite parts of  
Ruby, the Test::Unit module. I have some ideas for how to enhance it  
a bit.

First I just wanted to do a sanity check that I can make changes and  
see the effects. For some reason, no matter what I modify in my  
Test::Unit source code, my changes don’t seem to take effect.

For example, if I found unit.rb and added a puts statement:

at\_exit do  
unless $! || Test::Unit.run?  
puts “HELLO THERE!”  
exit Test::Unit::AutoRunner.run  
end  
end

but when I run my test (a simple ruby file that requires test/unit), I  
don’t see “HELLO THERE!”.

I also tried just reopening the class right above my test class  
definition:

module Test  
module Unit  
module UI  
module Console

```
    # Runs a Test::Unit::TestSuite on the console.
    class TestRunner
      def start
        output "Hello There!"
        setup_mediator
        attach_to_mediator
        return start_mediator
      end
    end
  end
end

```

end  
end

and still nothing.

What am I doing wrong?

Oh, ruby -v reports:  
ruby 1.8.6 (2007-03-13 patchlevel 0) [i686-darwin8.9.1]

Thanks  
Jeff

---

<div class="post-metadata">

**Author:** ![jeff](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jeff](https://www.ruby-forum.com/u/jeff)\
**Post date:** [September 17, 2007, 1:25pm UTC](https://www.ruby-forum.com/t/how-do-i-patch-test-unit/114694/2 "2007-09-17T13:25:16Z")

</div>

Perhaps my original post was too long or too obtuse… let me  
rephrase.

What’s the best way to extend then test/unit classes?

Thanks  
Jeff

---

<div class="post-metadata">

**Author:** ![jeff](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jeff](https://www.ruby-forum.com/u/jeff)\
**Post date:** [September 25, 2007, 11:00pm UTC](https://www.ruby-forum.com/t/how-do-i-patch-test-unit/114694/3 "2007-09-25T23:00:53Z")

</div>

On Sep 17, 11:50 am, Jay L. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Remember that the Mac comes with an old Ruby (1.8.2?) in /usr/bin, and  
> therefore probably an old Test::Unit in /usr/lib. Make sure you’re not  
> picking that up via $PATH; might just wanna delete it.

So it turns out that although I thought was saving my edits to  
unit.rb, in fact there was a permissions problem and TextMate wasn’t  
actually saving it.

Your idea about checking the path helped me figure it out.

Thanks.  
Jeff

---

<div class="post-metadata">

**Author:** ![jeff](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jeff](https://www.ruby-forum.com/u/jeff)\
**Post date:** [September 25, 2007, 11:05pm UTC](https://www.ruby-forum.com/t/how-do-i-patch-test-unit/114694/4 "2007-09-25T23:05:02Z")

</div>

Jeff,

I just tested the change to unit.rb that you mentioned, and it had the  
expected effect (printing “Hello there”). So I would make sure you’re  
editing the right file. If you are sure you are editing the right file,  
but still cannot get any result, try deleting it – then you’ll know for  
sure whether that file is being used.

As for not being able to edit the (open) classes, make sure you are  
editing the classes after you require the files, otherwise your changes  
will be overwritten. Also be very careful about namespaces / modules and  
such. I suggest not using any “include” statements, because they might  
introduce ambiguity. The important thing is that when you make a change  
to the class in question, you are changing the right class (and not just  
making a new one). When I ran “irb -r ‘test/unit’”, I found that the  
module Test::Unit::UI existed, but Test::Unit::UI::Console did not, so  
that might be your problem. (I just tested with “puts”.)

Finally, for which strategy you should use to extend these tools:  
-If your end goal is to make changes that you want distributed with the  
ruby standard library, you might as well patch the source directly.  
-If you intend to distribute your code as a library or gem, you had  
better reopen the class in a different file (not patch unit.rb), because  
it would be rude to ask users to make that change for the sake of your  
program. After all, it could break other programs.  
-If this is purely for personal use, you may do whichever is easier. The  
second way leaves you less likely to accidentally cripple your Ruby  
distribution.

Hope this helps,  
Dan

---

<div class="post-metadata">

**Author:** ![jeff](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jeff](https://www.ruby-forum.com/u/jeff)\
**Post date:** [September 25, 2007, 11:04pm UTC](https://www.ruby-forum.com/t/how-do-i-patch-test-unit/114694/5 "2007-09-25T23:04:02Z")

</div>

On Sep 16, 9:05 pm, Dan Z. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Jeff,
> 
> I just tested the change to unit.rb that you mentioned, and it had the  
> expected effect (printing “Hello there”). So I would make sure you’re  
> editing the right file. If you are sure you are editing the right file,  
> but still cannot get any result, try deleting it – then you’ll know for  
> sure whether that file is being used.

Thanks a lot, Dan. When you said this, it caused me to try the same  
thing on my Windows box, and it worked. So now I suspect it’s  
something about the way I’ve compiled/setup Ruby on my Mac laptop.

> As for not being able to edit the (open) classes, make sure you are  
> editing the classes after you require the files, otherwise your changes  
> will be overwritten. Also be very careful about namespaces / modules and  
> such. I suggest not using any “include” statements, because they might  
> introduce ambiguity. The important thing is that when you make a change  
> to the class in question, you are changing the right class (and not just  
> making a new one). When I ran “irb -r ‘test/unit’”, I found that the  
> module Test::Unit::UI existed, but Test::Unit::UI::Console did not, so  
> that might be your problem. (I just tested with “puts”.)

Interesting, I’ll be sure to watch out for these.

> Finally, for which strategy you should use to extend these tools:  
> -If your end goal is to make changes that you want distributed with the  
> ruby standard library, you might as well patch the source directly.  
> -If you intend to distribute your code as a library or gem, you had  
> better reopen the class in a different file (not patch unit.rb), because  
> it would be rude to ask users to make that change for the sake of your  
> program. After all, it could break other programs.  
> -If this is purely for personal use, you may do whichever is easier. The  
> second way leaves you less likely to accidentally cripple your Ruby  
> distribution.

Exactly - I’m hoping to distribute a library to our Ruby teams at  
work, so I’ll be re-opening the classes.

> Hope this helps,  
> Dan

It does! Thansk again. Maybe I’ll post again if I can find out what  
I’m doing wrong on my Mac environment.

Jeff

---

<div class="post-metadata">

**Author:** ![jeff](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jeff](https://www.ruby-forum.com/u/jeff)\
**Post date:** [September 25, 2007, 11:10pm UTC](https://www.ruby-forum.com/t/how-do-i-patch-test-unit/114694/6 "2007-09-25T23:10:37Z")

</div>

On Mon, 17 Sep 2007 13:13:01 +0900, Jeff wrote:

> Thanks a lot, Dan. When you said this, it caused me to try the same  
> thing on my Windows box, and it worked. So now I suspect it’s  
> something about the way I’ve compiled/setup Ruby on my Mac laptop.

Remember that the Mac comes with an old Ruby (1.8.2?) in /usr/bin, and  
therefore probably an old Test::Unit in /usr/lib. Make sure you’re not  
picking that up via $PATH; might just wanna delete it.