Python Testing with pytest

pytest is a popular Python testing framework that makes it easy to write and run automated tests.

Install pytest

              
            
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Install pytest using pip.
pip install pytest

Write Your First Test

              
            
Python
Create a simple test function.
def add(a, b):
    return a + b


def test_add():
    assert add(2, 3) == 5

Save the test in a file such as test_math.py and run pytest from the terminal.

Using Assertions

              
            
Python
Test different expected results.
def test_values():
    assert 10 > 5
    assert "python".upper() == "PYTHON"
    assert [1, 2] == [1, 2]

pytest Fixtures

Fixtures provide reusable setup data or resources for tests.

              
            
Python
Create and use a simple fixture.
import pytest

@pytest.fixture
def user():
    return {"name": "Alice", "age": 25}


def test_user(user):
    assert user["name"] == "Alice"

Test Exceptions

              
Python
Verify that a function raises an exception.
import pytest

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

def test_divide_by_zero():
    with pytest.raises(ZeroDivisionError):
        divide(10, 0)

Run Tests

              
            
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Run all pytest tests in the current project.
pytest

You can also run a specific test file by providing its filename, such as pytest test_math.py.

Summary

pytest provides a simple way to automate Python tests. Assertions verify results, fixtures provide reusable setup, and pytest.raises() checks expected exceptions.