pytest-remotedata

This package provides a plugin for the pytest framework that allows developers to control unit tests that require access to data from the internet. It was originally part of the astropy core package, but has been moved to a separate package in order to be of more general use.

Motivation

Many software packages provide features that require access to data from the internet. These features need to be tested, but unit tests that access the internet can dominate the overall runtime of a test suite.

The pytest-remotedata plugin allows developers to indicate which unit tests require access to the internet, and to control when and whether such tests should execute as part of any given run of the test suite.

Installation

The pytest-remotedata plugin can be installed using pip:

$ pip install pytest-remotedata

It is also possible to install the latest development version from the source repository:

$ git clone https://github.com/astropy/pytest-remotedata
$ cd pytest-remotedata
$ pip install .

In either case, the plugin will automatically be registered for use with pytest.

Usage

Installing this plugin makes two decorators available for use with pytest:

• remote_data for marking tests that require data from the internet
• internet_off for marking tests that should run only when internet access is disabled

These decorators can be used to mark test functions, methods, and classes using @pytest.mark. For example, consider the following test function that requires access to data from the internet:

import pytest
from urllib.request import urlopen

@pytest.mark.remote_data
def test_remote_data():
    urlopen('https://astropy.org')

Marking the test_remote_data function with @pytest.mark.remote_data indicates to pytest that this test should be run only when access to remote data sources is explicitly requested.

When this plugin is installed, the --remote-data command line option is added to the pytest command line interface.

The default behavior is to skip tests that are marked with remote_data. If the --remote-data option is not provided to the pytest command, or if --remote-data=none is provided, all tests that are marked with remote_data will be skipped. All tests that are marked with internet_off will be executed.

Sometimes it is useful to check that certain tests do not unexpectedly access the internet. Strict remote data access checking can be enabled by setting remote_data_strict = true in the tested package's setup.cfg file. If this option is enabled, any test that attempts to access the network but is not marked with @pytest.mark.remote_data will fail.

Providing either the --remote-data option, or --remote-data=any to the pytest command line interface will cause all tests that are marked with remote-data to execute. Any tests that are marked with internet_off will be skipped.

Running the tests with --remote-data=astropy will cause only tests that receive remote data from Astropy data sources to be run. Tests with any other data sources will be skipped. This is indicated in the test code by marking test functions with @pytest.mark.remote_data(source='astropy').

Running only the tests marked as remote_data, use the built-in pytest machinery, e.g., pytest -m remote_data --remote-data.

In the future, we intend to support a configurable way to indicate specific remote data sources in addition to astropy.

Development Status

Questions, bug reports, and feature requests can be submitted on github.

License

This plugin is licensed under a 3-clause BSD style license - see the LICENSE.rst file.