Test level shifter with Arduino and some data
You don't need to write any program. 

First, note that this is (or at least purports to be) an I2C level shifter. This means that it does not actively pull up anything; it only actively pulls down. You are supposed to provide pull-ups somewhere in your circuit.

To test it, pull up HV1 and LV1 with 10K resistors to HV and LV respectively; measure the voltage on both sides to verify you are pulling to ~5V and ~3.3V respectively.

Ground HV1, check that LV1 is low.

Ground LV1, check that HV1 is low.

Ta-dah!