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Advanced Pytest

🧪 Advanced Testing with Pytest

Pytest is the most popular testing framework for Python. It makes it easy to write small tests, yet scales to support complex functional testing.

🟢 Level 1: Foundations

1. Simple Assertions

Pytest uses standard Python assert statements.

def test_add():
    assert 1 + 1 == 2

2. Parameterization

Run the same test logic with multiple inputs.

import pytest

@pytest.mark.parametrize("input,expected", [(1, 2), (2, 3), (3, 4)])
def test_increment(input, expected):
    assert input + 1 == expected

🟡 Level 2: Fixtures (The Power of Pytest)

Fixtures provide a clean way to setup and teardown test data or resources.

@pytest.fixture
def db_connection():
    conn = connect_db()
    yield conn
    conn.close()

def test_query(db_connection):
    assert db_connection.query("SELECT 1") == 1

🔴 Level 3: Mocking & Patching

3. `unittest.mock` Integration

Use mocking to isolate the code under test from external dependencies like APIs or Databases.

from unittest.mock import patch

@patch("requests.get")
def test_api_call(mock_get):
    mock_get.return_value.status_code = 200
    # ... your test code ...