Hypothesis
==========

`Hypothesis <https://hypothesis.readthedocs.io/>`_ is a library that allows you
to write tests that are parameterised from a source of examples. It then
generates simple and understandable examples that can be used to make your tests
fail and find bugs with little effort.

#. Install Hypothesis:

   .. tab:: Linux/macOS

      .. code-block:: console

         $ python -m pip install hypothesis

   .. tab:: Windows

      .. code-block:: ps1con

         C:> python -m pip install hypothesis

   Alternatively, Hypothesis can also be installed with extensions, for example:

   .. tab:: Linux/macOS

      .. code-block:: console

         $ python -m pip install hypothesis[numpy,pandas]

   .. tab:: Windows

      .. code-block:: ps1con

         C:> python -m pip install hypothesis[numpy,pandas]

#. Write a test:

   #. Imports:

      .. literalinclude:: test_hypothesis.py
         :language: python
         :lines: 1-3
         :lineno-start: 1

   #. Test:

      .. literalinclude:: test_hypothesis.py
         :language: python
         :lines: 6-
         :lineno-start: 6

#. Perform test:

   .. tab:: Linux/macOS

      .. code-block:: console

           $ python -m pytest test_hypothesis.py
           ============================= test session starts ==============================
           platform darwin -- Python 3.13.0, pytest-8.3.3, pluggy-1.5.0
           rootdir: /Users/veit/cusy/trn/python-basics/docs/test
           plugins: hypothesis-6.114.1
           collected 1 item

           test_hypothesis.py F                                                     [100%]

           =================================== FAILURES ===================================
           __________________________________ test_mean ___________________________________

               @given(lists(floats(allow_nan=False, allow_infinity=False), min_size=1))
           >   def test_mean(ls):

           test_hypothesis.py:6:
           _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

           ls = [9.9792015476736e+291, 1.7976931348623157e+308]

               @given(lists(floats(allow_nan=False, allow_infinity=False), min_size=1))
               def test_mean(ls):
                   mean = sum(ls) / len(ls)
           >       assert min(ls) <= mean <= max(ls)
           E       assert inf <= 1.7976931348623157e+308
           E        +  where 1.7976931348623157e+308 = max([9.9792015476736e+291, 1.7976931348623157e+308])

           test_hypothesis.py:8: AssertionError
           ---------------------------------- Hypothesis ----------------------------------
           Falsifying example: test_mean(
               ls=[9.9792015476736e+291, 1.7976931348623157e+308],
           )
           =========================== short test summary info ============================
           FAILED test_hypothesis.py::test_mean - assert inf <= 1.7976931348623157e+308
           ============================== 1 failed in 0.44s ===============================

   .. tab:: Windows

      .. code-block:: ps1con

           C:> python -m pytest test_hypothesis.py
           ============================= test session starts ==============================
           platform win32 -- Python 3.13.0, pytest-8.3.3, pluggy-1.5.0
           rootdir: C:\Users\veit\python-basics\docs\test
           plugins: plugins: hypothesis-6.114.1
           collected 1 item

           test_hypothesis.py F                                                     [100%]

           =================================== FAILURES ===================================
           __________________________________ test_mean ___________________________________

               @given(lists(floats(allow_nan=False, allow_infinity=False), min_size=1))
           >   def test_mean(ls):

           test_hypothesis.py:6:
           _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

           ls = [9.9792015476736e+291, 1.7976931348623157e+308]

               @given(lists(floats(allow_nan=False, allow_infinity=False), min_size=1))
               def test_mean(ls):
                   mean = sum(ls) / len(ls)
           >       assert min(ls) <= mean <= max(ls)
           E       assert inf <= 1.7976931348623157e+308
           E        +  where 1.7976931348623157e+308 = max([9.9792015476736e+291, 1.7976931348623157e+308])

           test_hypothesis.py:8: AssertionError
           ---------------------------------- Hypothesis ----------------------------------
           Falsifying example: test_mean(
               ls=[9.9792015476736e+291, 1.7976931348623157e+308],
           )
           =========================== short test summary info ============================
           FAILED test_hypothesis.py::test_mean - assert inf <= 1.7976931348623157e+308
           ============================== 1 failed in 0.44s ===============================

.. seealso::
   `Hypothesis for the Scientific Stack
   <https://hypothesis.readthedocs.io/en/latest/numpy.html>`_