Performance testing best practices when doing TDD?

Question

I\'m working on a project which is in serious need of some performance tuning.

How do I write a test that fails if my optimizations do not in improve the speed of the pr

Answer 1

Not faced this situation yet ;) however if I did, here's how I'd go about it. (I think I picked this up from Dave Astel's book)

Step#1: Come up with a spec for 'acceptable performance' so for example, this could mean 'The user needs to be able to do Y in N secs (or millisecs)'
Step#2: Now write a failing test.. Use your friendly timer class (e.g. .NET has the StopWatch class) and Assert.Less(actualTime, MySpec)
Step#3: If the test already passes, you're done. If red, you need to optimize and make it green. As soon as the test goes green, the performance is now 'acceptable'.