How to Run Specific Test in pytest: Simple Guide

To run a specific test in pytest, use the command pytest -k <test_name> where <test_name> matches the test function name or part of it. You can also run a test by specifying its file and function like pytest path/to/test_file.py::test_function.

Syntax

There are two main ways to run a specific test in pytest:

• By test name pattern: Use pytest -k <expression> where <expression> matches test names.
• By file and test function: Use pytest <path>::<test_function> to run a single test function in a file.

This lets you focus on one test without running the entire suite.

bash

pytest -k test_name_part
pytest tests/test_example.py::test_specific_function

Example

This example shows how to run a specific test function named test_addition inside test_math.py.

python

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

def test_subtraction():
    assert 2 - 1 == 1

# Run this specific test with:
# pytest test_math.py::test_addition

Output

============================= test session starts =============================
collected 2 items

test_math.py::test_addition PASSED                                      [100%]

============================== 1 passed in 0.01s ==============================

Common Pitfalls

Common mistakes when running specific tests include:

• Using -k with a wrong or partial test name that matches multiple tests unintentionally.
• Forgetting to specify the full path and function name with ::, causing pytest to run the whole file.
• Not escaping special characters in test names when using -k.

Always double-check the test name and path to avoid running more tests than intended.

bash

## Wrong way: runs all tests in the file
pytest test_math.py

## Right way: runs only one test function
pytest test_math.py::test_addition

Quick Reference

Command	Description
pytest -k test_name_part	Run tests matching the name pattern
pytest path/to/file.py::test_function	Run a specific test function in a file
pytest -m marker_name	Run tests with a specific marker (advanced)

Key Takeaways

Use pytest -k <test_name> to run tests matching a name pattern.

Use pytest <file>::<test_function> to run one test function exactly.

Check test names carefully to avoid running unintended tests.

Specify full file path and function name for precise test runs.

Markers can also filter tests but require prior setup.