Provides a constant sample integer value for test fixtures.

Enables test functions to reference a deterministic constant through pytest dependency injection rather than hardcoding values inline.

Unit testing: multiple test functions need the same predictable integer input. Test fixtures: providing a simple stub value for assertions against a known constant. Pytest: declaring a reusable constant via the fixture mechanism so tests stay decoupled from literal values.

Unit test fixtures, mocking, test fixtures in pytest.

def fixture_name(): return literal_value

def ...(): return ...

fixture_name: identifier for the fixture function, literal_value: constant value to return

• pytest.fixture decorator
• conftest.py
• assert statements
• test_ prefixed functions
• capsys

• return 0 (neutral zero value but may mask off-by-one errors)
• return None (signals absence
• unsuitable for numeric assertions)
• yield value (adds teardown support
• overkill for simple constants)

Forgetting @pytest.fixture decorator — fixture will not be discovered by pytest and tests will fail with fixture-not-found error. Returning a mutable object like a list — caller may mutate it causing test interference between test runs. Naming fixture identically to a module-level variable — pytest resolution may shadow the module variable unexpectedly.

pytest parametrize (provides multiple inputs per test run vs single constant), yield-based fixture (supports setup/teardown lifecycle vs simple return), factory fixture (returns a callable that generates fresh values vs returning a fixed constant)

Coming from unittest: may define helper methods on TestCase class instead of using pytest fixture injection — pytest resolves fixtures by argument name, not by self attributes.

• test_fixture

Avoid for non-trivial setup; if the value needs computation or I/O, use a yield-based fixture instead. Returning a constant has negligible performance cost but creates tight coupling if the same constant appears in multiple assertion points and later needs to change. Do not use when tests need independent mutable copies — return a factory or use deep copies instead.

Gives test code a deterministic value to assert against.

Think of the answer to life, the universe, and everything.

Simple fixture returning the integer 42, often used as a placeholder in test suites.

Consider parameterizing the fixture to return multiple values.