Identify as many questionable or incorrect assumptions as you can in the following statement:
Testers run tests, and running tests requires that the code be written, and no code is available until the end of the first iteration. Therefore, the earliest the tester is needed is the end of iteration 1.
1.
Testers run tests. In fact, testers perform many other activities, including identifying hidden assumptions (wow, this is recursive), helping the customer write acceptance tests, estimating time for acceptance test tasks, and helping the team accurately estimate each story.
2.
Running tests requires that the code be written. This may sound like a stretch, but other things besides code require testing. Identifying hidden assumptions in stories is one example of a test on something besides code. Usability testing a user interface is another. It's also a good idea to "test" user documentation.
3.
No code is available until the end of the first iteration. Programmers will produce working code the first day. It's possible to do testing that goes beyond unit testing even before all the code for a single story is completed. For example, a programmer may spike a design and want to have it load-tested to make sure it's scalable.
4.
The earliest a tester is needed is the end of iteration 1. See points 1 3.
