'pytest' exits with no error, but with "collected 0 items"

Question

I have been trying to run unit tests using pytest in Python. I had written a module with one class and some methods inside that class. I wrote a unit test for this module (with a simple assert statement to check equality of lists) where I first instantiate the class with a list. Then I invoke a method on that object (from the class). Both test.py and the script to be tested are in the same folder. When I run pytest on it, I get "collected 0 items".

I am new to pytest, and but I am unable to run their examples successfully. What am I missing here?

I am running Python version 3.5.1 and pytest version 2.8.1 on Windows 7.

My test.py code:

from sort_algos import Sorts  def integer_sort_test():     myobject1 = Sorts([-100, 10, -10])     assert myobject1.merge_sort() == [-101, -100, 10] 

sort_algos.py is a module containing class Sorts. merge_sort is a method under Sorts.

Answer 1

pytest gathers tests according to a naming convention. By default any file that is to contain tests must be named starting with test_, classes that hold tests must be named starting with Test, and any function in a file that should be treated as a test must also start with test_.

If you rename your test file to test_sorts.py and rename the example function you provide above as test_integer_sort, then you will find it is automatically collected and executed.

This test collecting behavior can be changed to suit your desires. Changing it will require learning about configuration in pytest.

Answer 2

I had the same issue, but my function was called test.py. I never thought that the issue would be the file name.

In the documentation it says:

pytest will run all files of the form test_*.py or *_test.py in the current directory and its subdirectories. More generally, it follows standard test discovery rules.

Exactly! The name should be test_.py or test_something.py and works for me.

I feel so stupid, hehe.