Why keeping a backlog on index cards is a good idea...

Portability - easy to pick up the cards and take them wherever.

Easy to prioritise - put them on a table and shuffle them.

Focused - there's not much you can write on an index card so only the most important information will be written on them.

Low maintenance - all you need is a pencil and a pile of index cards, and if something changes tear up the current card and write a new one.

What is a test stub?

A test stub replaces a real component on which part of the system under test (SUT) relies.

A stub is used to inject the SUT with indirect inputs allowing the test to execute different paths through the SUT.

There are two types of test stub - a responder and a saboteur. A responder injects valid values and a saboteur injects errors or exceptions.