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Quick HOWTO
-----------
  
  Simply run the following in the top source directory:
  
    perl Makefile.PL
    make test

Dependencies
------------

  Apart from the test modules (Test::More, Test::Exception and so on), the
  Image::ExifTool library is required. Even though the program itself supports
  running with either Image::ExifTool as well as Image::Info, it would be to
  complex to support both backend libraties for unit tests. Therefore the
  latter library is only supported on a "best-effort" basis.

Purpose
-------

  The tests have a dual purpose. I use them as part of test-driven development,
  so they basically define the code architecture. They also serve as a
  regression test suite.

Kinds of tests
--------------

  We have:

   - unit tests: testing classes individually, in separation from each other.
     Any necessary instances of other classes should be mocked.

   - integration tests: testing larger test cases involving interactions of
     objects of different classes

Organization
------------

  Although test ordering itself should not matter, it does make sense to run
  the unit tests before integration tests. The reason is that if some change
  breaks both kinds of tests, seeing the unit tests failure at the beginning
  will make it easier to find the cause (integration tests are usually more
  complicated).

  Additionally, having the biggest integration test execute as last, makes it
  easy to visually inspect the program behaviour in a relatively interesting
  use case.

  Therefore we have a naming convention which makes the unit tests run before
  all other tests. Also, integration tests which use less classes should be put
  before those which use more classes, if possible.

  Ordering is possible because the perl testing framework runs them in filename
  alphabetical order.

Notes
-----

Things to keep in mind when changing/adding tests:
 - they should succeed in any timezone and any locale: you can check that by
   running for example:

   LANG=C TZ=GMT make test
   LANG=pl_PL.UTF-8 TZ=America/Los_Angeles make test

   before that make sure your system supports the locale you are testing with (try "LANG=pl_PL.UTF-8 locale")