Testing Types
=============

Three types of tests:

- Unit

- Integration

- Functional

Unit Tests
----------

Unit tests are tests which test a *unit* of code.  In Python, the unit is
almost alwas a method or a function.

Python's standard module for performing unit testing is ``unittest``.

Integration Tests
-----------------

Integration tests are tests which verify that two parts of a system are
collaborating as expected.

Python's standard module for performing unit testing is *also* (confusingly)
``unittest``.

Functional Tests
----------------

Functional tests are end-to-end tests of a complete application.  Also known as
"system tests".

Python does not really have a standard library for doing functional tests.  I
tend to use ``unittest``.

When Do I Write Which Ones?
---------------------------

- Ideally, you at two of the three: unit and functional.

- Reasonable people can disagree on the importance of their proportions to each
  other within the test base of an application.

- I tend to write mostly unit tests.  I write almost no integration tests.  I
  write a few functional tests to make sure everything is working right and
  that I haven't mocked myself into placation.