Testing
=======

Installing Pytest
-----------------
**In Repl.it**: 
On the right tab, click the ``Packages`` icon. Search for ``pytest`` and add it to the project.

**At Home**:
In your terminal type ``$ pip install pytest``

Creating a test file
--------------------
Your test file should be a separate file from the code you wish to test. Always name your test files according to the following rules:

1. Start with ``test_``
2. Include the name of what you are testing
3. End with ``.py``

Some good examples:

- ``test_vector.py``
- ``test_sleep_in.py``
- ``test_main.py``


Writing tests
-------------
In the :ref:`test file <testing:Creating a test file>`:

1. Import the function you want to test.
2. Create a test function starting with ``test_``
3. Write :ref:`testing:Assertions` to test the function you want to test.

Assertions
^^^^^^^^^^
Assertions consist of two main parts.

1. Calling the function you want to test (:ref:`with arguments <functions:Passing arguments>`)
2. Comparing the actual result to an expected result.

.. code-block:: python

    # a general assertion pattern
    assert some_function() == "expected result"

    # some specific examples
    assert add(5, 7) == 12
    assert add(1, 1) == 2

    assert say_hello("Dave") == "Hello, Dave."
    assert say_hello("Mr. Gallo") == "Hello, Mr. Gallo."


A complete test file
^^^^^^^^^^^^^^^^^^^^

.. code-block:: python

    from main import add, say_hello

    
    def test_add():
        assert add(5, 7) == 12
        assert add(1, 1) == 2


    def test_say_hello():
        assert say_hello("Dave") == "Hello, Dave."
        assert say_hello("Mr. Gallo") == "Hello, Mr. Gallo."


Running Pytest
--------------
In the terminal, just type ``pytest``. Alternatively, if you want to run a single, specific test file, you include the name of that file. For example ``pytest test_main.py``.


Testing Object Attributes
-------------------------

.. code-block:: python

    # test_animal.py

    from animal import Animal


    def test_can_create_animal():
        a = Animal("Homo", "Sapiens")
        assert a.genus == "Homo"
        assert a.species == "Sapiens"
        assert a.happiness == 100

.. code-block:: python

    # animal.py

    class Animal:
        def __init__(self, genus: str, species: str):
            self.genus = genus
            self.species = species
            self.happiness = 100

Testing Object Methods
----------------------

.. code-block:: python

    # test_animal.py

    def test_eat():
        dog = Animal("Canis", "Familiaris")
        dog.eat()
        assert dog.happiness == 150

        dog.eat()
        dog.eat()
        assert dog.happiness == 250

    def test_sleep():
        dog = Animal("Canis", "Familiaris")
        dog.sleep(5)
        assert dog.happiness == 160

        # Shouldn't award points for sleeping 0 hours
        cat = Animal("Blah", "Whocares")
        cat.sleep(0)
        assert cat.happiness == 100

.. code-block:: python

    # animal.py

    class Animal:
        def __init__(self, genus: str, species: str):
            self.genus = genus
            self.species = species
            self.happiness = 100
        
        def __str__(self) -> str:
            return f"{self.genus} {self.species}"
        
        def eat(self) -> None:
            self.happiness += 50

        def sleep(self, time: int) -> None:
            if time > 0:
                self.happiness += 2*time + 50