pytest-csv-params

A pytest plugin to parametrize tests by CSV files.

Requirements

• Python 3.8, 3.9 or 3.10
• pytest >= 7.1

There's no operating system dependend code in this plugin, so it should run anywhere where pytest runs.

Installation

Simply install it with pip...

pip install pytest-csv-params

... or poetry ...

poetry add --dev pytest-csv-params

Usage

Simply decorate your test method with @csv_params and the following parameters:

Parameter	Type	Description	Example
data_file	str	The CSV file to use, relative or absolute path	/var/testdata/test1.csv
base_dir	str (optional)	Directory to look up relative CSV files (see data_file)	join(dirname(__file__), "assets")
id_col	str (optional)	Column name of the CSV that contains test case IDs	ID#
dialect	csv.Dialect (optional)	CSV Dialect definition (see [1])	csv.excel_tab
data_casts	dict (optional)	Cast Methods for the CSV Data (see "Data Casting" below)	{ "a": int, "b": float }

[1] Python CSV Documentation

Data Casting

When data is read from CSV, they are always parsed as str. If you need them in other formats, you can set a method that should be called with the value.

These methods can also be lambdas, and are also good for further transformations.

Data Casting Example

from pytest_csv_params.decorator import csv_params

def normalize(x: str) -> str:
    return x.strip().upper()

@csv_params(
    data_file="/test/data.csv",
    data_casts={
        "col_x": normalize,
        "col_y": float,
    },
)
def test_something(col_x, col_y):
    # Test something...
    ...

CSV Format

The default CSV format is:

• \r\n as line ending
• All non-numeric fields are surrounded by "
• If you need a " in the value, use "" (double quote)
• Fields are separated by comma (,)

Example CSV

"ID#", "part_a", "part_b", "expected_result"
"first", 1, 2, 3
"second", 3, 4, 7
"third", 10, 11, 21

Usage Example

This example uses the CSV example from above.

from pytest_csv_params.decorator import csv_params

@csv_params(
    data_file="/data/test-lib/cases/addition.csv",
    id_col="#ID",
    data_casts={
        "part_a": int,
        "part_b": int,
        "expected_result": int,
    },
)
def test_addition(part_a, part_b, expected_result):
    assert part_a + part_b == expected_result

Contributing

Build and test

You need Poetry in order to build this project.

Tests are implemented with pytest, and tox is used to orchestrate them for the supported python versions.

• Checkout this repo
• Run poetry install
• Run poetry run tox (for all supported python versions) or poetry run pytest (for your current version)

Bugs etc.

Please send your issues to csv-params_issues (at) jued.de. Please include the following:

• Plugin Version used
• Pytest version
• Python version with operating system

It would be great if you could include example code that clarifies your issue.

Pull Requests

Pull requests are always welcome. Since this Gitea instance is not open to public, just send an e-mail to discuss options.

License

Code is under MIT license. See LICENSE.txt for details.