doctestcase 0.2.0

Evaluate doctests with configurable globals and `setUp`–`tearDown`. Export to Markdown and reST to include in docs.

doctestcase

Evaluate doctests with configurable globals and setUp–tearDown. Format as Markdown and reST to include in docs.

Features

• Evaluate doctests
• Configure doctest globals and setUp–tearDown
• Relies on unittest.TestCase
• Minimalistic decorator-based API
• Format docstring as Markdown and reST to include in docs
• Naturally fits docsub-based pipeline
• No dependencies
• Checked with mypy
• 100% test coverage
• Tested with Python 2.7+

Alternatives

• doctest.DocTestSuite allows to run doctests with unittest, but individual doctests can't be extended, parametrized, or enclosed with setUp–tearDown.

Installation

$ pip install doctestcase

Use cases

• Decorated TestCase
• Reuse __doctestcase__ from other TestCase
• Parametrize test case
• Inherit from decorated TestCase
• Format docstring as Markdown or reStructuredText
• Integration with docsub

See API Reference for details.

Decorated TestCase

from doctest import ELLIPSIS
from unittest import TestCase

from doctestcase import doctestcase


@doctestcase(globals={'X': 'yz'}, options=ELLIPSIS)
class SimpleCase(TestCase):
    """
    Title

    Paragraph.

    >>> X * 100
    'yzyz...'

    Another paragraph.

    >>> None
    >>> True
    True
    """

    def test_custom(self):  # called before 'test_docstring'
        self.assertTrue(True)

    def test_other(self):  # called after 'test_docstring'
        self.assertTrue(True)

All test methods are called by unittest in alphabetic order, including test_docstring, added by @doctestcase.

Reuse __doctestcase__ from other TestCase

Extending example above,

@SimpleCase.__doctestcase__
class AnotherCase(TestCase):
    """
    Title

    >>> X * 100
    'yzyz...'
    """

Now AnotherCase.__doctestcase__ holds shallow copy of globals, kwargs, and same doctest options, as SimpleCase. These copies are independent.

Inherit from decorated class

Inheriting from another test case decorated with @doctestcase allows to reuse and extend globals and kwargs and override doctest options of the base class.

Extending examples above,

@doctestcase(globals={'A': 'bc'})
class InheritedCase(SimpleCase):
    """
    Title

    >>> (X + A) * 100
    'yzbcyzbc...'
    """

Notice that global variable A was added to globals defined in SimpleCase, and the new class reuses doctest.ELLIPSIS option.

For more details on how doctestcase properties are updated, check the API Reference.

Parametrize doctest case

First, define base class parametrized with cwd:

from doctest import ELLIPSIS
import os.path
import shutil
import tempfile
from unittest import TestCase, skip

from doctestcase import doctestcase


@skip('base class')
@doctestcase(options=ELLIPSIS, cwd='.')
class ChdirTestCase(TestCase):
    def setUp(self):
        self.temp = tempfile.mkdtemp()
        self.prev = os.getcwd()
        cwd = os.path.join(self.temp, self.__doctestcase__.kwargs['cwd'])
        if not os.path.exists(cwd):
            os.mkdir(cwd)
        os.chdir(cwd)

    def tearDown(self):
        os.chdir(self.prev)
        shutil.rmtree(self.temp)

Notice how the base class is skipped from testing.

In this example we use os.path module for compatibility with older Python versions only. If you use recent Python versions, use pathlib instead.

Now we can define test case parametrized with cwd:

@doctestcase(cwd='subdir')
class Case1(ChdirTestCase):
    """
    >>> import os
    >>> os.getcwd()
    '.../subdir'
    """

Inherit from decorated TestCase

Test cases, decorated with @doctestcase, can be used as base classes for other test cases. This is useful when inherited classes need to extend or change properties, passed to parent's @doctestcase. Parent properties will be copied and updated with values from child class decorator.

For the SimpleCase class above,

@doctestcase(globals={'A': 'bc'})
class InheritedCase(SimpleCase):
    """
    Title

    >>> (X + A) * 100
    'yzbcyzbc...'
    """

Format docstring as Markdown or reStructuredText

For the SimpleCase class above,

Markdown

>>> from doctestcase import to_markdown
>>> to_markdown(SimpleCase)

## Title

Paragraph.

```pycon
>>> X * 100
'yzyz...'
```

Another paragraph.

```pycon
>>> None
>>> True
True
```

reStructuredText

>>> from doctestcase import to_rest
>>> to_rest(SimpleCase)

Title
-----

Paragraph.

>>> X * 100
'yzyz...'

Another paragraph.

>>> None
>>> True
True

Integration with docsub

When documenting packages, "Usage" section often includes doctests. It is a good practice to test all documented use cases, so why not adopt test-driven documenting approach and write tests with docs in mind?

1. Write tests with carefully crafted docstrings using doctests.
2. Include generated Markdown or reST in docs.

With docsub, this can be achieved with some minimal configuration.

Just two commands to run tests and update docs:

$ pytest tests
$ docsub sync -i usage.md

usage.md

# Usage

<!-- docsub: begin -->
<!-- docsub: x case tests/test_usage.py:UseCase1 -->
## Use Case 1

Long description of the use case.

Usage example in doctest:

```pycon
>>> True
True
```
<!-- docsub: end -->

tests/test_usage.py

from unittest import TestCase

from doctestcase import doctestcase


@doctestcase()
class UseCase1(TestCase):
    """
    Use Case 1

    Long description of the use case.

    Usage example in doctest:

    >>> True
    True
    """

docsubfile.py

Docsub configuration file declaring project-local x-tension command:

from docsub import click
from doctestcase import to_markdown
from importloc import Location


@click.group()
def x() -> None:
    pass


@x.command()
@click.argument('case')
def case(case: str) -> None:
    text = to_markdown(Location(case).load(), title_depth=2)
    click.echo(text, nl=False)

See also

• Project documentation
• Project changelog