Hypothesis
==========

`Hypothesis <https://hypothesis.readthedocs.io/>`_ ist eine Bibliothek, mit der
ihr Tests schreiben könnt, die aus einer Quelle von Beispielen :term:`
`parametrisiert <Parameter>` werden. Anschließend werden einfache und
verständliche Beispiele generiert, die dazu verwendet werden können, eure Tests
fehlschlagen zu lassen und Fehler mit wenig Aufwand zu finden.

#. Installiert Hypothesis:

   .. tab:: Linux/macOS

      .. code-block:: console

         $ python -m pip install hypothesis

   .. tab:: Windows

      .. code-block:: ps1con

         C:> python -m pip install hypothesis

   Alternativ kann Hypothesis auch mit Erweiterungen installiert werden, z.B.:

   .. 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]

#. Schreibt einen Test:

   #. Importe:

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

   #. Testen:

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

#. Test durchführen:

   .. tab:: Linux/macOS

      .. code-block:: pytest

         $ 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:: pytest

         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>`_