Expyct
======

*Partial matching of any Python object.*

Using Expyct is a good idea when you need to assert something in a test case but there is some non-determinism.

For example, rounding errors prevent you from comparing a :code:`float` exactly. Or a timestamp is created on-the-fly, and therefore changes every test run.

In these cases, you need to be able to set specific constraints on the expected value. That is what **Expyct** is for!

The constraints can be provided as constructor arguments. For example :code:`n == Number(min=3, max=5)` is only true when :code:`n` is between 3 and 5.

Some other examples of classes are :code:`Float`, :code:`String`, :code:`Any` and :code:`DateTime`. As you can see, they closely match the built-in Python types.

The library also comes with many commonly used data validators like :code:`ANY_UUID` which matches any UUID string. And :code:`TODAY` which matches any `datetime` occurring on the current day.

Checking nested data structures is easy as well:

.. code-block:: python

    import expyct as exp
    from datetime import datetime


    def test_my_function():
        result = my_function()

        assert result == {
            "first_name": exp.String(regex="(mary)|(peter)", ignore_case=True),
            "last_name": "Johnson",
            "signup_date": exp.DateTime(after=datetime(2020, 1, 2), before=datetime(2020, 3, 5)),
            "details": {
                "number": exp.Int(min=2),
                "amount": exp.Float(close_to=2.3, error=0.001),
                "purchases": exp.List(exp.Dict(keys={"id", "product", "category"}), non_empty=True),
            },
            "time_of_purchase": exp.OneOf([exp.TODAY, exp.THIS_HOUR]),
            "type": exp.AnyType(subclass_of=str),
            "item_ids": exp.Set(subset_of=[1, 2, 3]),
            "metadata": exp.Dict(keys_any=exp.Collection(superset_of=["a", "b"])),
            "context": exp.ANY,
        }

.. toctree::
   :hidden:

   self
   installation

.. toctree::
   :caption: Modules

   expyct.any
   expyct.base
   expyct.collection
   expyct.combination
   expyct.datetime
   expyct.number
   expyct.string