# Error while testing a new block

**URL:** <https://www.ruby-forum.com/t/error-while-testing-a-new-block/214022>\
**Category:** GNU Radio\
**Created:** [November 18, 2011, 7:21pm UTC](https://www.ruby-forum.com/t/error-while-testing-a-new-block/214022 "2011-11-18T19:21:50Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![luislavena](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/0ea827/32.png) [@luislavena](https://www.ruby-forum.com/u/luislavena)\
**Post date:** [November 18, 2011, 7:21pm UTC](https://www.ruby-forum.com/t/error-while-testing-a-new-block/214022/1 "2011-11-18T19:21:50Z")

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Hello!

I was learning how to make a block, using the “how to make a block  
tutorial”, and when I develop a little block for tests, I got the error  
message displayed below. The error occurred when i ran the python tests.

## ====================================================================== ERROR: test\_001\_quad\_ff ( **main**.qa\_rtdsp)

Traceback (most recent call last):  
File “./qa\_rtdsp.py”, line 29, in setUp  
self.fg = gr.flow\_graph ()  
AttributeError: ‘module’ object has no attribute ‘flow\_graph’

======================================================================

Also, it isn’t clear for me exactly what files should I change to be  
able  
to compile the new block. If I make modifications only in the files  
listed  
on the tutorial, the make command indicate error in some other files.  
So,  
basically, I’m opening every file from the example and checking if they  
have any references to the block I develop. Is this the correct  
approach?  
Do I have to change all those files?

---

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**Author:** ![SSAndrSS\_SelvaSS\_SS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/f05b48/32.png) [@SSAndrSS\_SelvaSS\_SS](https://www.ruby-forum.com/u/SSAndrSS_SelvaSS_SS)\
**Post date:** [November 18, 2011, 8:06pm UTC](https://www.ruby-forum.com/t/error-while-testing-a-new-block/214022/2 "2011-11-18T20:06:57Z")

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On Fri, Nov 18, 2011 at 1:20 PM, Andr S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> File “./qa\_rtdsp.py”, line 29, in setUp  
> Do I have to change all those files?
> 
> –  
> Andr F. B. Selva

What version are you running? The use of “flow\_graph” has long been  
dead.

Make sure you have the latest version of howto-write-a-block and  
gnuradio (  
[http://gnuradio.org/redmine/projects/gnuradio/wiki/Download](http://gnuradio.org/redmine/projects/gnuradio/wiki/Download)).

Tom

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<div class="post-metadata">

**Author:** ![SSAndrSS\_SelvaSS\_SS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/f05b48/32.png) [@SSAndrSS\_SelvaSS\_SS](https://www.ruby-forum.com/u/SSAndrSS_SelvaSS_SS)\
**Post date:** [July 9, 2013, 6:16am UTC](https://www.ruby-forum.com/t/error-while-testing-a-new-block/214022/3 "2013-07-09T06:16:32Z")

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change flow\_graph to top\_block

---

<div class="post-metadata">

**Author:** ![SSAndrSS\_SelvaSS\_SS](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/f05b48/32.png) [@SSAndrSS\_SelvaSS\_SS](https://www.ruby-forum.com/u/SSAndrSS_SelvaSS_SS)\
**Post date:** [November 18, 2011, 8:10pm UTC](https://www.ruby-forum.com/t/error-while-testing-a-new-block/214022/4 "2011-11-18T20:10:03Z")

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On 11/18/2011 10:20 AM, Andr S. wrote:

> File “./qa\_rtdsp.py”, line 29, in setUp  
> self.fg = gr.flow\_graph ()  
> AttributeError: ‘module’ object has no attribute ‘flow\_graph’

That looks like the old API which was deprecated years ago. Its not  
gr.top\_block() Perhaps you should take a look at the latest howto.

My personal favorite howto:  
[http://gnuradio.org/cgit/gnuradio.git/tree/gr-howto-write-a-block-cmake](http://gnuradio.org/cgit/gnuradio.git/tree/gr-howto-write-a-block-cmake)

-Josh