I just wrote a nice Led Strip Simulator and thought it would be worth sharing it with you.
Results are instant, no compiling/upload processes that would slow down the development.
The API is as close to the Adafruit_NeoPixel library (https://github.com/adafruit/Adafruit_NeoPixel) as possible.
Here is the ready-to-use online version (http://htmlpreview.github.io/?https://github.com/T-vK/LedStripSimulator/blob/master/index.html)
And here is the whole Github project (https://github.com/T-vK/LedStripSimulator)
Screenshot
(https://github.com/T-vK/LedStripSimulator/raw/master/screenshot.jpg) (http://htmlpreview.github.io/?https://github.com/T-vK/LedStripSimulator/blob/master/index.html)