How do I use Jest?
Who needs Jest?
People who write code with release dates. There’s always pressure to write more code as a way to get more features by a certain date, but too much code in too short a time hurts quality, which threatens both features and release dates.
What if I can’t limit the size of my code?
You can reduce it. Knowing a good target and how far you’ve gone past that target is a good start.
Is Jest a planning and estimation tool?
Not in the traditional sense. Plans and estimates are traditionally used to decide whether the project is worth attempting and to pass judgment on those doing the work. Jest is meant to be used by those doing the work to focus their efforts.
Isn’t lines of code a bad metric?
That depends on what you’re measuring. If you want to measure the size of your accomplishment, lines of code is a lousy metric. If you want to measure the amount of testing, QA, and communication needed to get your code right, lines are a decent approximation.
How does Jest work?
Jest uses the COCOMO II formulas developed at the University of Southern California. USC provides several proprietary implementations and an on-line version. There are also other proprietary programs that use these formulas.
Unfortunately, none of those programs are code budgeters. They use the same formulas, but for a different purpose.
For all the details on the inner workings of jest, take a look at the source code.
Where does the name come from?
It used to be an acronym, but now it’s just a reminder not to take the numbers too seriously and a source of bad puns.