This test application will initialize a Groove LED bar with the configuration as specified in the grove_ledbar_params.h file. To connect the LED bar with your board use the following pinout:

Pin GND is connected directly to GND.
Pin VCC is connected directly to VCC +3.3V, or 5V if your board allows that.
Pin DCKI is the clock pin and is connected to a free GPIO
Pin DI is the data pin and is connected to a free GPIO, too

for the 2 latter pins note the port and pin number and adapt the Makefile accordingly.

The test application will light up the LED bar several times, running from 0% up to 100% and down to 0% again.