PyTest: "no tests ran" even though tests were clearly run

I have the following config file for pytest:

[pytest] 
filterwarnings = 
    ignore::DeprecationWarning
    ignore::UserWarning 

python_files = 
    test_file_1.py 
    test_file_2.py

log_cli = True 
log_level = INFO

I run pytest locally with the following command:

python -m pytest path

and get the output

====================================================================================================== no tests ran in 24.77s =======================================================================================================

which I cannot believe, since before, I get the following output in the terminal (because of the logging):

INFO     root:test_file_1.py:40 torch.Size([100, 71])

I noticed that if I remove the filterwarnings in pytest.ini, I get a warnings summary, but not the output "no tests ran".

What exactly is happening here? Why does filterwarnings lead to the output "no tests ran"?

Solution

pytest expects test methods to be named a certain way. Eg def test_1():.

If you just throw python code into a file and run it with pytest:

import time

time.sleep(2)

You'll see: no tests ran in 2.01s.

But if you have a method that starts with test_ in your file and run it with pytest:

import time

def test_1():
    time.sleep(2)

You'll see: 1 passed in 2.01s.

So it's important to follow the naming conventions set by pytest if you want your tests to be discovered. (More info on discovery rules: https://docs.pytest.org/en/latest/example/pythoncollection.html)

Have your files start with test_, and have your methods start with test_ so that the default pytest discovery rules find your tests.