How do I write tests using pytest?

How do I write tests using pytest?

To write tests using pytest, you need to create a Python file that starts with 'test_' and define functions that also start with 'test_'. You can use assertions to check if the output is as expected.

Can you show me a simple example?

Sure! Here's a simple example:

# test_sample.py

def add(a, b):
    return a + b


def test_add():
    assert add(1, 2) == 3
    assert add(-1, 1) == 0

You can run this test by executing pytest test_sample.py in your terminal.

What if I want to test for exceptions?

You can use the pytest.raises context manager to test for exceptions. Here's an example:

import pytest

def divide(a, b):
    return a / b


def test_divide_by_zero():
    with pytest.raises(ZeroDivisionError):
        divide(1, 0)

This will check that dividing by zero raises a ZeroDivisionError.

How do I organize my tests in a larger project?

In larger projects, it's common to organize tests in a separate directory, often named 'tests'. You can create subdirectories for different modules and use naming conventions to keep your tests structured.