Develop Reference

Can't get PyTest to run in VSCode or terminal. No tests recognized

I have installed pytest using pip. Sample code below
import pytest
def example():
assert 9 == 9
My settings.json file looks like this
{
"python.testing.pytestArgs": [
"."
],
"python.testing.unittestEnabled": false,
"python.testing.nosetestsEnabled": false,
"python.testing.pytestEnabled": true
}
I keep getting no tests ran in terminal when using the pytest filename.py command.
Python version : 3.9.1
pytest version : 6.2.2.
Anyone have any ideas?
Update: Jason's answer below is what worked. The problem was the naming of the file and methods. File name needed to end in '_test.py' for vscode to run tests and functions needed to start with 'test_' for both terminal and vscode to run.

Try renaming the file to "test_filename.py" and the test function to "test_example" so that they are detected by pytest.
https://docs.pytest.org/en/reorganize-docs/new-docs/user/naming_conventions.html
Also, a useful pytest option for debugging the ability to run tests is "--collect-only". It will attempt to only find tests without running them.
pytest --collect-only
VSCode has the ability to run tests itself, without you executing them in the terminal.
https://code.visualstudio.com/docs/python/testing

Pylint with sniffer not using updated source files

I am using Pylint and Nose along with sniffer to lint and test my python application on every save. This is sniffer in case you are unaware https://pypi.python.org/pypi/sniffer
Here is the runnable responsible for running nosetests and pylint from scent.py file for sniffer
from sniffer.api import * # import the really small API
from pylint import lint
from subprocess import call
import os
import nose
#runnable
def zimmer_tests(*args):
command = "nosetests some_module/test --nologcapture --with-coverage --cover-config-file=zimmer_coverage_config"
lint.Run(['some_module/app'], exit=False)
return call(command, shell=True) == 0
Here, first lint.Run() runs pylint on my app. Then nosetest is executed on the app using call()
The Problem is that after I save the file nosetests run on updated version of the file however Pylint uses the same old version. I have to restart sniffer every time for pylint to get new version of files.
I assume this is not a problem of sniffer's configuration since nosetests is able to get the new version of file every time. Still I am not sure.
My pylintrc file is almost the same we get from generate command pylint --generate-rcfile > .pylintrc with some minor application specific tweaks.

As pointed by #KlausD. in comments, the lint.Run() was using files from cache as it was being called from a still running process. Calling pylint from command line worked as expected.
Here is the modified code
#runnable
def zimmer_tests(*args):
command_nose = "nosetests some_module/test --nologcapture --with-coverage --cover-config-file=zimmer_coverage_config"
command_lint = "pylint some_module"
call(command_lint, shell=True)
return call(command_nose, shell=True) == 0

Python: How to run tests made with unittest

This is the structure of my project, and I would like to run the test that I have made from the command line.
I am using the following command:
python test_hotel.py
However I am getting the following error
ImportError: No module named 'hotel'
What can I do to solve this problem, and is there a way to execute the whole tests in a project from the command line.
Thanks in advance.

For running unittest from commandline, you should use this command:
python -m unittest tests.test_hotel
You need to make sure that you have followed the rules in writing unittests (https://docs.python.org/2/library/unittest.html)

As #shahram kalantari said to run a tests the command line is:
python -m unittest tests.test_hotel
If one wants to run the whole tests the command line is:
python -m unittest discover tests
If you want more information about what tests were run the -v flag should be included:
python -m unittest discover tests -v

How to debug unittests with pudb debugger?

I am having some trouble trying to debug some unit tests through the pudb debugger.
The tests run fine with python, but I had no luck runnign them with pudb.
I isolated the problem, getting to the following sample code:
class Math:
def pow(self, x, y):
return x ** y
import unittest
class MathTest(unittest.TestCase):
def testPow23(self):
self.assertEquals(8, Math().pow(2, 3))
def testPow24(self):
self.assertEquals(16, Math().pow(2, 4))
if __name__ == '__main__':
unittest.main()
The tests run fine:
$ python amodule.py
.
----------------------------------------------------------------------
Ran 2 tests in 0.001s
OK
But if running through pudb, it gives me the output:
----------------------------------------------------------------------
Ran 0 tests in 0.000s
OK
I've tried running using pudb amodule.py and also with python -m pudb.run amodule.py, but it makes no difference -- no tests are run in one or another way.
Should I be doing something different to debug unit tests using pudb?

Try placing a breakpoint on a useful line in your code:
from pudb import set_trace; set_trace()
The ways you tried to launch it might interfere with test discovery and/or not run your script with a __name__ of '__main__'.

Since this is a popular question, I feel I should also mention that most test running tools will require you to pass in a switch to prevent it from capturing the standard output and input (usually it's -s).
So, remember to run pytest -s when using Pytest, or nosetests -s for Nose, python manage.py test -s for Django tests, or check the documentation for your test running tool.

You can set a breakpoint even easier by:
import pudb; pu.db

Debugging pytest post mortem exceptions in pycharm/pydev

I would like to use the built in Pytest runner of PyCharm together with the debugger without pre-configuring breakpoints.
The problem is that exceptions in my test are caught by Pytest so PyCharm's post mortem debugger cannot handle the exception.
I know using a breakpoint works but I would prefer not to run my test twice.
Found a way to do this in Unittest, I would like to know if something like this exists in Pytest.
Is there a way to catch unittest exceptions with PyCharm?

Are you using pytest-pycharm plugin? Looks like it works for me. Create virtualenv, pip install pytest pytest-pycharm, use this virtualenv at PyCharm Edit configuration -> Python Interpreter and then run with Debug ... Example:
import pytest
def test_me():
assert None
if __name__ == '__main__':
pytest.main(args=[__file__])
PyCharm debugger stops at assert None point, with (<class '_pytest.assertion.reinterpret.AssertionError'>, AssertionError(u'assert None',), None)
EDIT
Set Preferences > Tools > Python Integration Tools > Default test runner to py.test. Then Run > Debug 'py.test in test_me.py'