# AssertionError: Could not find pytest

**URL:** <https://discourse.openrobotics.org/t/assertionerror-could-not-find-pytest/3969>\
**Category:** ROS General\
**Created:** [February 14, 2018, 2:23am UTC](https://discourse.openrobotics.org/t/assertionerror-could-not-find-pytest/3969 "2018-02-14T02:23:55Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![RAM46](https://avatars.discourse-cdn.com/v4/letter/r/77aa72/32.png) [@RAM46](https://discourse.openrobotics.org/u/RAM46)\
**Post date:** [February 14, 2018, 2:23am UTC](https://discourse.openrobotics.org/t/assertionerror-could-not-find-pytest/3969/1 "2018-02-14T02:23:55Z")

</div>

I used the below link to build ros2,

> **[GitHub - ros2/ros2: The Robot Operating System, is a meta operating...](https://github.com/ros2/ros2)**
>
> The Robot Operating System, is a meta operating system for robots.

when i tried testing and running using,

> python src\ament\ament\_tools\scripts\ament.py test

> python src\ament\ament\_tools\scripts\ament.py test\_results

i got an error,

Traceback (most recent call last):  
File “src\ament\ament\_tools\scripts\ament.py”, line 161, in   
sys.exit(main() or 0)  
File “C:\dev\ros2\src\ament\ament\_tools\ament\_tools\commands\ament.py”, line 88, in main  
rc = args.main(args)  
File “C:\dev\ros2\src\ament\ament\_tools\ament\_tools\verbs\test\cli.py”, line 60, in main  
build\_main(opts, test\_pkg\_main\_wrapper)  
File “C:\dev\ros2\src\ament\ament\_tools\ament\_tools\verbs\build\cli.py”, line 172, in main  
return iterate\_packages(opts, packages, per\_package\_main)  
File “C:\dev\ros2\src\ament\ament\_tools\ament\_tools\verbs\build\cli.py”, line 300, in iterate\_packages  
rc = process\_sequentially(jobs)  
File “C:\dev\ros2\src\ament\ament\_tools\ament\_tools\verbs\build\cli.py”, line 340, in process\_sequentially  
rc = job’callback’  
File “C:\dev\ros2\src\ament\ament\_tools\ament\_tools\verbs\test\cli.py”, line 50, in test\_pkg\_main\_wrapper  
rc = test\_pkg\_main(opts)  
File “C:\dev\ros2\src\ament\ament\_tools\ament\_tools\verbs\test\_pkg\cli.py”, line 83, in main  
handle\_build\_action(on\_test\_ret, context)  
File “C:\dev\ros2\src\ament\ament\_tools\ament\_tools\verbs\build\_pkg\cli.py”, line 268, in handle\_build\_action  
for build\_action in build\_action\_ret:  
File “C:\dev\ros2\src\ament\ament\_tools\ament\_tools\build\_types\ament\_python.py”, line 118, in on\_test  
assert pytest, ‘Could not find pytest’  
AssertionError: Could not find pytest

Please help me get over this issue. Thanks.

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<div class="post-metadata">

**Author:** ![wjwwood](https://sea2.discourse-cdn.com/flex022/user_avatar/discourse.openrobotics.org/wjwwood/32/13715_2.png) [@wjwwood](https://discourse.openrobotics.org/u/wjwwood)\
**Post date:** [February 14, 2018, 3:41am UTC](https://discourse.openrobotics.org/t/assertionerror-could-not-find-pytest/3969/2 "2018-02-14T03:41:55Z")

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Did you do this line from those instructions?

> pip install nose coverage mock pytest pytest-cov pytest-runner