nti.testing 4.4.0
Support for testing code
License: Apache
Requires Python: >=3.10
Keywords: nose2 testing zope3 ZTK hamcrest

=============
 nti.testing
=============

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Support for writing tests, particularly in a Zope3/ZTK environment,
using zope.testing (nose2 may also work, but is not recommended).

Complete documentation is hosted at https://ntitesting.readthedocs.io/

Installation
============

nti.testing can be installed using pip, either from the git repository
or from PyPI::

  pip install nti.testing[testgres]

Use the ``testgres`` extra to be able to use `nti.testing.layers.postgres`.

PyHamcrest
==========

nti.testing provides a group of `PyHamcrest`_ matchers. There are both
general-purpose matchers and matchers that are of use to users of
`zope.interface`_ and `zope.schema`_.


.. _PyHamcrest: https://pyhamcrest.readthedocs.io/en/latest/
.. _zope.interface: https://pypi.python.org/pypi/zope.interface
.. _zope.schema: https://pypi.python.org/pypi/zope.schema

.. NOTE: We rely on the Sphinx 'default_role' to turn single back quotes into links,
   while still being compatible with rendering with plain docutils/readme_renderer
   for PyPI.

Matchers can be imported from the `nti.testing.matchers` module; the most commonly used matchers
can be directly imported from `nti.testing`.

Basic Matchers
--------------

`is_true` and `is_false` check the `bool` value of a supplied
object (we're using literals for explanation purposes, but it
obviously makes more sense, and reads better, when the matched object
is a variable, often of a more complex type):

   >>> from hamcrest import assert_that, is_
   >>> from nti.testing import is_true, is_false
   >>> assert_that("Hi", is_true())
   >>> assert_that(0, is_false())

Interface Matchers
------------------

Next we come to matchers that support basic use of ``zope.interface``.

We can check that an object provides an interface and that a factory
implements it:

   >>> from zope.interface import Interface, Attribute, implementer
   >>> class IThing1(Interface):
   ...     pass
   >>> class IThing2(Interface):
   ...     pass
   >>> class IThings(IThing1, IThing2):
   ...     got_that_thing_i_sent_you = Attribute("Did you get that thing?")
   >>> @implementer(IThings)
   ... class Thing(object):
   ...     def __repr__(self): return "<object Thing>"

   >>> from nti.testing import provides, implements
   >>> assert_that(Thing(), provides(IThings))
   >>> assert_that(Thing, implements(IThings))

The attentive reader will have noticed that ``IThings`` defines an
attribute that our implementation doesn't *actually* provide. This is
where the next stricter check comes in. `verifiably_provides` uses
the interface machinery to determine that all attributes and methods
specified by the interface are present as described:

  >>> from nti.testing import verifiably_provides
  >>> assert_that(Thing(), verifiably_provides(IThing2, IThing1))
  >>> assert_that(Thing(), verifiably_provides(IThings))
  Traceback (most recent call last):
  ...
  AssertionError:...
  Expected: object verifiably providing <...IThings>
       but: Using class <class 'Thing'> the object <object Thing> has failed to implement interface ....IThings: The ....IThings.got_that_thing_i_sent_you attribute was not provided.
  <BLANKLINE>

If multiple attributes or methods are not provided, all such missing
information is reported:

  >>> class IThingReceiver(IThings):
  ...    def receive(some_thing):
  ...        """Get the thing"""
  >>> @implementer(IThingReceiver)
  ... class ThingReceiver(object):
  ...     def __repr__(self): return "<object ThingReceiver>"
  >>> assert_that(ThingReceiver(), verifiably_provides(IThingReceiver))
  Traceback (most recent call last):
  ...
  AssertionError:...
  Expected: object verifiably providing <...IThingReceiver>
       but: Using class <class 'ThingReceiver'> the object <object ThingReceiver> has failed to implement interface ....IThingReceiver:
            The ....IThings.got_that_thing_i_sent_you attribute was not provided
            The ....IThingReceiver.receive(some_thing) attribute was not provided
  <BLANKLINE>

``zope.interface`` can only check whether or not an attribute or
method is present. To place (arbitrary) tighter constraints on the
values of the attributes, we can step up to ``zope.schema`` and the
`validly_provides` matcher:

  >>> from zope.schema import Bool
  >>> class IBoolThings(IThing1, IThing2):
  ...     got_that_thing_i_sent_you = Bool(required=True)
  >>> @implementer(IBoolThings)
  ... class BoolThing(object):
  ...     def __repr__(self): return "<object BoolThing>"

`validly_provides` is a superset of `verifiably_provides`:

  >>> from nti.testing import validly_provides
  >>> assert_that(BoolThing(), validly_provides(IThing1, IThing2))
  >>> assert_that(BoolThing(), validly_provides(IBoolThings))
  Traceback (most recent call last):
  ...
  AssertionError:...
  Expected: (object verifiably providing <...IBoolThings> and object validly providing ....IBoolThings)
       but: object verifiably providing <....IBoolThings> Using class <class 'BoolThing'> the object <object BoolThing> has failed to implement interface ....IBoolThings: The ....IBoolThings.got_that_thing_i_sent_you attribute was not provided.
  <BLANKLINE>

For finer grained control, we can compare data against schema fields
using `validated_by` and `not_validated_by`:

  >>> from nti.testing import validated_by, not_validated_by
  >>> field = IBoolThings.get('got_that_thing_i_sent_you')
  >>> assert_that(True, is_(validated_by(field)))
  >>> assert_that(None, is_(not_validated_by(field)))

Parent/Child Relationships
--------------------------

The `aq_inContextOf` matcher uses the concepts from `Acquisition` to
check parent/child relationships:

  >>> from nti.testing import aq_inContextOf
  >>> class Parent(object):
  ...     pass
  >>> class Child(object):
  ...     __parent__ = None
  >>> parent = Parent()
  >>> child = Child()
  >>> child.__parent__ = parent

  >>> assert_that(child, aq_inContextOf(parent))

Test Fixtures
=============

Support for test fixtures can be found in `nti.testing.base` and
`nti.testing.layers`. The ``base`` package includes fully-fleshed
out base classes for direct use, while the ``layers`` package mostly includes
mixins that can be used to construct your own test layers.

The ``base`` package makes a distinction between "normal" and "shared"
fixtures. Normal fixtures are those that are used for a single test
case. They are established via ``setUp`` and torn down via
``tearDown``.

In contrast, shared fixtures are expected to endure for the duration
of all the tests in the class or all the tests in the layer. These are
best used when the fixture is expensive to create. Anything that
extends from `nti.testing.base.AbstractSharedTestBase` creates a shared fixture.
Through the magic of metaclasses, such a subclass can also be assigned
as the ``layer`` property of another class to be used as a test layer
that can be shared across more than one class.

The most important bases are `nti.testing.base.ConfiguringTestBase` and
`nti.testing.base.SharedConfiguringTestBase`. These are both fixtures for
configuring ZCML, either from existing packages or complete file
paths. To use these, subclass them and define class attributes
``set_up_packages`` and (if necessary) ``features``:

  >>> from nti.testing.base import ConfiguringTestBase
  >>> import zope.security
  >>> class MyConfiguringTest(ConfiguringTestBase):
  ...     set_up_packages = (
  ...         'zope.component', # the default configuration by name
  ...          # a named file in a named package
  ...          ('ftesting.zcml', 'zope.traversing.tests'),
  ...          # an imported module
  ...          zope.security,
  ...          # Our own package; in a test, this will mean the parent
  ...          # package
  ...          ".")

We would then proceed to write our test methods. The packages that we
specified will be set up and torn down around every test method. In
addition, the ``zope.testing`` cleanup functions will also run around
every test method.

Time
====

Having a clock that's guaranteed to move in a positive increasing way
in every call to ``time.time`` is useful. `nti.testing.time`
provides a decorator to accomplish this that ensures values always are
at least the current time and always are increasing. (It is not thread
safe.) It can be applied to functions or methods, and optionally takes
a ``granularity`` argument:

  >>> from nti.testing import time_monotonically_increases
  >>> from nti.testing.time import reset_monotonic_time
  >>> @time_monotonically_increases(0.1) # increment by 0.1
  ... def test():
  ...     import time
  ...     t1 = time.time()
  ...     t2 = time.time()
  ...     assert t2 == t1 + 0.1, (t2, t1)

  >>> test()

And The Rest
============

There are some other assorted utilities, including support for working with
ZODB in `nti.testing.zodb`. See the API documentation for details.


=========
 Changes
=========

4.4.0 (2025-11-14)
==================

- Move ZODB and related dependencies to the optional 'zodb' extra.
- Add support for Python 3.14.


4.3.0 (2025-04-22)
==================

- Support and require testgres version 1.11. This version refactored
  some internals, breaking the monkey-patches that ``DatabaseLayer``
  applies.


4.2.0.post0 (2024-11-08)
========================

- Nothing changed yet.


4.2.0 (2024-11-06)
==================

- Add support for Python 3.13.
- Use native namespace packages.


4.1.0 (2024-04-10)
==================

- Add support for, and require, testgres 1.10. This is needed because
  they changed the signature for ``get_pg_version``.
- Drop support for Python 3.8 and 3.9.


4.0.0 (2023-10-24)
==================

- Add support for Python 3.10, 3.11 and 3.12.
- Drop support for Python 2 and Python 3.6 and 3.7.
- Add a layer for working with a ``testgres`` Postgres instance.
- Add methods to the test base classes to support ``unittest.mock`` patches.


3.1.0 (2021-09-08)
==================

- Add support for Python 3.9.

- Drop support for Python 3.5.

- Add the module alias ``nti.testing.mock``, which is either the
  standard library ``unittest.mock``, or the backport ``mock``. This
  allows easy imports when backwards compatibility matters.

- Make ``mock``, ``mock.Mock`` and various other API attributes,
  like ``is_true``, available directly from the ``nti.testing`` namespace.

3.0.0 (2020-06-16)
==================

- Add support for Python 3.8.

- Require zope.interface 5.1. This lets the interface matchers produce
  much more informative error messages.

- Add ``nti.testing.zodb`` with helpers for dealing with ZODB. This
  makes ZODB 5.6 or above a required dependency.

2.2.1 (2019-09-10)
==================

- Make transaction cleanup safer if the default transaction manager
  has been made explicit.

  Also, reset the default transaction manager to implicit.

  See `issue 17 <https://github.com/NextThought/nti.testing/issues/17>`_.


2.2.0 (2018-08-24)
==================

- Add support for Python 3.7.

- Make ``time_monotonically_increases`` also handle ``time.gmtime``
  and add a helper for using it in layers.


2.1.0 (2017-10-23)
==================

- Make ``Acquisition`` an optional dependency. If it is not installed,
  the ``aq_inContextOf`` matcher will always return False.

- Remove dependency on ``fudge``. Instead, we now use ``unittest.mock`` on
  Python 3, or its backport ``mock`` on Python 2. See `issue 11
  <https://github.com/NextThought/nti.testing/issues/11>`_.

- Refactor ZCML configuration support to share more code and
  documentation. See `issue 10
  <https://github.com/NextThought/nti.testing/issues/10>`_.

- The layer ``ConfiguringLayerMixin`` and the base class
  ``SharedConfiguringTestBase`` now default to running
  configuration in the package the subclass is defined in, just as
  subclasses of ``ConfiguringTestBase`` did.

2.0.1 (2017-10-18)
==================

- The validation matchers (``validated_by`` and ``not_validated_by``)
  now consider it a failure (by default) if the validate method raises
  anything other than ``zope.interface.exceptions.Invalid`` (which
  includes the ``zope.schema`` exceptions like ``WrongType``).
  Previously, they accepted any exception as meaning the object was
  invalid, but this could hide bugs in the actual validation method
  itself. You can supply the ``invalid`` argument to the matchers to
  loosen or tighten this as desired. (Giving ``invalid=Exception``
  will restore the old behaviour.)
  See `issue 7 <https://github.com/NextThought/nti.testing/issues/7>`_.


2.0.0 (2017-04-12)
==================

- Add support for Python 3.6.

- Remove ``unicode_literals``.

- Substantially rework ``time_monotonically_increases`` for greater
  safety. Fixes `issue 5 <https://github.com/NextThought/nti.testing/issues/5>`_.

1.0.0 (2016-07-28)
==================

- Add Python 3 support.

- Initial PyPI release.