[pytest best practices] Some pytest best practices #python #pytest

pytest.ini

[pytest]
# Default options:
#   - `--tb=line` stand for shorter traceback format (only one line per failure)
#   - `-rfEPpxX` Select the short summary info to display
# See https://docs.pytest.org/en/latest/usage.html#modifying-python-traceback-printing
addopts = --tb=line -rfEPpxX
log_cli = 1
log_cli_level = INFO
log_cli_format = %(asctime)s [%(levelname)8s] %(message)s (%(filename)s:%(lineno)s)
log_cli_date_format=%Y-%m-%d %H:%M:%S

test_sample.py

# content of test_sample.py
import logging
import pytest

logger = logging.getLogger(__name__)

# using arguments to be able to identify them easily
# ease parametrization in a second step
def test_eval_operation(operation="3 + 4", expected=6):
    # instead of commenting logging a clear message saying what is tested
    test_that = f"{operation} = {expected}"
    logger.info(f"Test that {test_that}")
    actual = eval(operation)
    # actual left, expected right
    # proper error message with error left and what we got right
    assert actual == expected, f"{test_that} failed, got {actual}"


# More information on parametrize -> https://docs.pytest.org/en/latest/parametrize.html
@pytest.mark.parametrize(
    "operation,expected",
    [("2 + 4", 6), pytest.param("3 + 4", 6, marks=pytest.mark.xfail)],
)
def test_eval_operation_param(operation, expected):
    test_that = f"{operation} = {expected}"
    logger.info(f"Test that {test_that}")
    actual = eval(operation)
    assert actual == expected, f"{test_that} failed, got {actual}"