https://github.com/jimfulton/testvars

Helper for making assertions on complex data structures with variable parts.
https://github.com/jimfulton/testvars

python test-framework testing testing-framework

Last synced: about 1 year ago
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Helper for making assertions on complex data structures with variable parts.

• Host: GitHub
• URL: https://github.com/jimfulton/testvars
• Owner: jimfulton
• License: mit
• Created: 2017-07-07T14:28:24.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2017-07-07T14:38:21.000Z (almost 9 years ago)
• Last Synced: 2025-03-17T07:09:59.926Z (over 1 year ago)
• Topics: python, test-framework, testing, testing-framework
• Language: Python
• Size: 4.88 KB
• Stars: 2
• Watchers: 0
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.rst
  • Changelog: CHANGES.rst
  • License: LICENSE.txt

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README

          
===================================================

testvars - Place-holders in complex test assertions

===================================================

Sometimes, when writing tests, you want to assert that a data

structure computed in a test matches some expected value, but the

expected value might have components, such as times or generated ids

that can't be predicted ahead of time.  Options in this situation

include:

- break the assertion into many assertions about various parts of the

  data structure.

- Use mocking/stubbing to control things like time and ids to make

  unpredictable parts of the data predictable.

Both of these approaches tend to be pretty tedious and potentially

error prone.

The tiny testvars package provides an alternative that is much easier

to use in many cases.  The package provides a ``Vars`` class::

  >>> import testvars

  >>> vars = testvars.Vars()

When ``Vars`` attributes are compared equal the first time, the

comparison succeeds and alse sets their value:

  >>> vars.x == 1

  True

At that point, the value is set, and you can make assertions

against it:

  >>> vars.x

  1

  >>> vars.x > 0

  True

Further comparisons are against this set value:

  >>> vars.x == 2

  False

This is useful when dealing with data structures with unpredictable

parts:

  >>> expected = {'id': vars.child_id, 'name':"Alex"}

  >>> {'id': 32, 'name':"Alex"} == expected

  True

It's also interesting when, while you don't know what values will be,

you can make assertions about how values are related:

  >>> expected = {'id': vars.parent_id, 'name':'Cas',

  ...             'children': [vars.child_id]}

  >>> expected == {'id': 42, 'name':'Cas', 'children':[32]}

  True

  >>> expected == {'id': 42, 'name':'Cas', 'children':[33]}

  False

  >>> [vars.y, 2, 3, vars.y] == [9, 2, 3, 9]

  True

  >>> [vars.z, 2, 3, vars.z] == [8, 2, 3, 9]

  False