Sometimes quick experiments in IPython grow large and you find yourself wanting unit tests. This module aims to make testing code in IPython notebooks easy. At its core, it offers a way to run pytest tests inside the notebook environment. It is also designed to make the transfer of the tests into proper python modules easy.

Installation: pip install ipytest

Features:

• support for pytest inside notebooks (with all bells and whistles)
• tight integration with IPython via magics and automatic code transforms

• 0.4.0: add support for automatic AST transforms, deprecated non pytest API. Currently in beta, use ipytest==0.4.0b1.
• 0.3.0: change default pattern for clean_tests to match pytest discovery
• 0.2.2: add support for assert rewriting with current pytest versions
• 0.2.1: add ipython magics to simplify test execution
• 0.2.0: support for using pytest inside notebooks
• 0.1.0: support for running unittest.FunctionTestCase, unittest.TestCases, and doctests.

For usage see the example notebook or the documentation for the core API below.

The suggested way to import ipytest is:

import ipytest
import ipytest.magics

ipytest.config.rewrite_asserts = True

IPython magic that first executes the cell, then executes run_pytest. Any arguments passed on the magic line be passed on to pytest. To register the magics, run import ipytest.magics first.

For example:

%%run_pytest -qq


def test_example():
    ...

Same as the %%run_pytest, but cleans any previously found tests, i.e., only tests defined in the current cell are executed. To register the magics, run import ipytest.magics first.

ipytest.run(*args)

Execute all tests in the passed module (defaults to main) with pytest.

• args (any): additional commandline options passed to pytest
• module (any): the module containing the tests. If not given, main will be used.
• filename (any): the filename of the file containing the tests. It has to be a real file, e.g., a notebook name, since itts existence will be checked by pytest. If not given, the file attribute of the passed module will be used.
• plugins (any): additional plugins passed to pytest.

ipytest.clean_tests(pattern=None, items=None)

Delete tests with names matching the given pattern.

In IPython the results of all evaluations are kept in global variables unless explicitly deleted. This behavior implies that when tests are renamed the previous definitions will still be found if not deleted. This method aims to simply this process.

An effecitve pattern is to start with the cell containing tests with a call to clean_tests, then defined all test cases, and finally call run_tests. This way renaming tests works as expected.

Arguments:

• pattern: a glob pattern used to match the tests to delete.
• • items: the globals object containing the tests. If None is given, the: globals object is determined from the call stack.

ipytest.reload(*mods)

Reload all modules passed as strings.

This function may be useful, when mixing code in external modules and notebooks.

Usage:

reload("ipytest._util", "ipytest")

Configure ipytest. The following settings are suported:

• ipytest.config.rewrite_asserts: enable ipython AST transforms to rewrite asserts, defaults to False.
• ipytest.config.clean: the patter used to clean variables, defaults to [Tt]est*.

To execute the unit tests of ipytest run

pipenv sync --dev
pipenv run test

Before commit execute pipenv run precommit to update the documentation, format the code, and run tests.

Rewrite any asserts in the current cell using pytest without running the tests. To get best results run the tests with run_pytest. To register the magics, run import ipytest.magics first.

For example::

%%rewrite_asserts

def test_example():
    ...

ipytest.run_pytest(*args, **kwargs)

Execute tests in the passed module (defaults to main) with pytest.

Arguments:

• module: the module containing the tests. If not given, main will be used.
• filename: the filename of the file containing the tests. It has to be a real file, e.g., a notebook name, since itts existence will be checked by pytest. If not given, the file attribute of the passed module will be used.
• pytest_options: additional options passed to pytest
• pytest_plugins: additional plugins passed to pytest.

ipytest.run_tests(*args, **kwargs)

Run all tests in the given items dictionary.

Arguments:

• doctest: if True search for doctests.
• • items: the globals object containing the tests. If None is given, the: globals object is determined from the call stack.

ipytest.collect_tests(*args, **kwargs)

Collect all test cases and return a unittest.TestSuite.

The arguments are the same as for ipytest.run_tests.

ipytest.assert_equals(*args, **kwargs)

Compare two objects and throw and exception if they are not equal.

This method uses ipytest.get_assert_function to determine the assert implementation to use depending on the argument type.

Arguments

• a, b: the two objects to compare.
• • args, kwargs: (keyword) arguments that are passed to the underlying: test function. This option can, for example, be used to set the tolerance when comparing numpy.array objects

ipytest.get_assert_function(*args, **kwargs)

Determine the assert function to use depending on the arguments.

If either object is a numpy .ndarray, a pandas.Series, a pandas.DataFrame, or pandas.Panel, it returns the assert functions supplied by numpy and pandas.

ipytest.unittest_assert_equals(*args, **kwargs)

Compare two objects with the assertEqual method of unittest.TestCase.

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Copyright (c) 2015 - 2018 Christopher Prohm

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