As you're writing tests for the normal conditions, it might be good to codify 
your assumptions about how the objects handle the edge cases, which are often called FencePost or OffByOne (Obi-Wan) errors.

'''General Boundary Conditions''':

* Uninitialised -- (Language/compiler dependent: 0, NULL or random value.) How does the code behave when it gets a null value instead of a real object? Does it segfault? Throw an exception? Return an object after the NullObject pattern?

'''Collection Boundary Conditions''':

* Collections include arrays, linked-lists, SQL R''''''esultSets, the "Game" class in the ObjectMentorBowlingGame. Here are five specific conditions to test when developing such a class:
** Empty
** Minimum
** Maximum
** Minimum - 1 -- invalid index just below the expected range of values
** Maximum + 1 -- invalid index just above the expected range of values

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CategoryTesting